Python Tutorial - Prime Numbers | Program To Check Entered Number is Prime or Not

In this python programming video tutorial you will learn about the prime numbers in detail with different examples.
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. Here we will discuss how to write python program to check whether the entered number is prime or not.
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[@manishbaburaisingh1985]

Simple and good .need more videos on the programs which are general in interviews

[@AmulsAcademy]

Sure:) Thank you:)

[@priyankavaidya110]

Thank you so much for explaining with example. I was confused with for loop. Now ,it is completely clear to me ....how it works.

[@AmulsAcademy]

Glad it was helpful! :)

[@nehajoshi4978]

after watching so mny videos i understood from yours ty:-):-)

[@AmulsAcademy]

Glad to hear that :)

[@Engineer9060]

how you understood tell me also its totally wrong code ,it is for even no. when you will do it for 21 it will show prime but 21 is not prime....

[@abhishekpani6735]

Thanku so much .. it really helped me...❤️

[@AmulsAcademy]

Glad to hear that :)

[@shruthisagar7677]

Hi . Very well explained . Easy to understand and solve it Thank You

[@AmulsAcademy]

Welcome:)

[@omkar1592]

your voice and explanation both are amazing

[@AmulsAcademy]

Thank you 😊

[@darthsidious1137]

Wish I would of found this video a couple hours ago. Had to settle with the brute force method for my assignment.

[@galadimatimothy802]

Well done.. Perfectly explained

[@AmulsAcademy]

Thank you :)

[@Pikachu-dw3qk]

mam please say how this technique applies if we give input number 2 ??? for other numbers i understood this code perfectly except number 2 case please reply mam

[@AmulsAcademy]

When input is 2, for loop body will not execute and else part will execute :) In for loop start is 2 and end is 2 so it won’t execute loop body :) And because for loop is not terminated by break statement , else par will execute :)

[@Pikachu-dw3qk]

@@AmulsAcademy ok mam i got it thanks for the reply

[@hmx21]

You don't need to check all the way till num, running the loop till num//2 would get you the same result.

[@DrRCB]

yes. However there is still a shorter range than n/2.

[@okechukwuerinne2039]

I tried this and got a wrong output. I got "4 is a prime number." Perhaps I messed up the program somewhere.

[@lolbaba7403]

@@okechukwuerinne2039 number=2 divisor=2 if number ==divisor or number==1: print("prime number") else: if number%divisor==0: print("Not prine") else: print("Prime") This is code for short range. But when it comes to find prime number in some range then this code is wrong.

[@shayaanrk]

@@okechukwuerinne2039 for such basic exceptions, you should have already added another if statement. if num%2==0 then print False

[@trundlingwithjoy2237]

thank you for this keep up the good work

[@AmulsAcademy]

Thank you 😊❤️

[@rajangymtech.7073]

Your teching ideas mind blowing

[@amansharma-it4df]

Very good video you solve me very very big problem thank you very much again

[@listentosilently]

Video is good #TECH_INTERVIEW_PREPRATION

[@AmulsAcademy]

Thank you 😊

[@listentosilently]

🙏🙏🙏

[@radiagulzan]

Thank you so much! But, what do we do with the input 2 in the end?

[@AmulsAcademy]

2 is a prime number :)

[@darshanchaudhari9836]

Bro same doubt , did you get the answer

[@okechukwuerinne2039]

Thank you so much for this; it was a life saver.

[@obulasettyganesh8920]

🤣🤣🤣🤣

[@jnageswararao8574]

U voice is good....

[@dudeinspace1491]

Ur voice keeps entertaining..!

[@gandrakavya8201]

thank you mam!!!....ur vedios make me to solve programs on my own :)

[@daniellejdevlin8882]

Can you explain why number=2 shows up as prime in the code when 2÷2=0? I know 2 is prime

[@AmulsAcademy]

Check for loop range 😊

[@unclerojelio6320]

There is not need to check the for divisors greater than sqrt(num). You can increase the efficiency of this program quite a bit by changing the for loop to: for i in range(2, sqrt(num))

[@tuomasbazzan1523]

Thank you

[@AmulsAcademy]

Pleasure :)

[@ganpatinatrajan5890]

Excellent Explanations...👍👍👍

[@lilyfullery4779]

Too good ❤

[@possiblesupport1029]

Super explaination on the whole youtube

[@vidithnarayana2346]

I like your explanation 👌👌 TQ so much

[@deepikamathur9466]

Nice mam..

[@AmulsAcademy]

Thank you :)

[@shivabagareddy9195]

Good explanation with impressive voice..... Want to listen more of your voice:)

[@AmulsAcademy]

Thank you :)

[@SanOp-zx1pc]

this code is wrong input numbers like 27,321,etc... which are not divisible by 2 but are not prime numbers.... still the programme gives the numbers to be prime correct programme code num=int(input('Enter a positive number :')) if num > 1: # Iterate from 2 to n / 2 for i in range(2, int(num/2)+1): # If num is divisible by any number between # 2 and n / 2, it is not prime if (num % i) == 0: print(num, "is not a prime number") break else: print(num, "is a prime number") elif num==0: print(num,'is neither prime nor composite.....') else: print(num, "is not a prime number")

[@SanOp-zx1pc]

@@A4KSHAT Bro is 27 a prime number??? ofcourse not , so how it is showing that it is a prime number

[@A4KSHAT]

@@SanOp-zx1pc i am sorry it is show it is not a prime number

[@dharmikmistry8781]

It's very good 👏👏👍

[@Sandeep-sh7uc]

You wrote print(num,"is not a prime number" ) in FOR loop why it is not printing for num number of times

[@ahinav.s1925]

Thanks

[@aniketpatil1737]

I am watching this masterpiece in Dec 2021

[@itzscytesalpha2963]

Nice vid

[@AmulsAcademy]

Thank you :)

[@Raja-tt4ll]

Great explanation thanks

[@AmulsAcademy]

Thank you :)

[@gayathrishanmuganathan4205]

you explained it very Well

[@AmulsAcademy]

Thank you :)

[@Engineer9060]

no she explained wrong go for 21,9

[@gayathridevip4632]

Sisy.. plz put videos for sum of next 2 consecutive numbers

[@AmulsAcademy]

Will try 😊

[@tanweerkarzai7355]

withought using breal ,how to solve it

[@ameyashetty1441]

hey 2 is a prime no but 2%2==0 then how does this work

[@AmulsAcademy]

Please check for loop range, starting value and end value is same that is 2, so it won’t execute loop body 😊

[@nandithaarunshetty1473]

@@AmulsAcademy no it's not same it becomes(2,1) right as end value is excluded

[@swathinagarajan4804]

Tq mam

[@AmulsAcademy]

Pleasure 😊

[@nishasrinivasan4621]

Thank you so much for this

[@AmulsAcademy]

My Pleasure :)

[@bakrymohamed8711]

my teacher I think we don't need the break statement so that after the if condition becomes false the for else will work

[@AmulsAcademy]

The else block just after for/while is executed only when the loop is NOT terminated by a break statement. So you need to break statement here. Note: remove break and try to execute the program.

[@bakrymohamed8711]

@@AmulsAcademy right

[@vishaljat4398]

Thank you❤

[@nareshchoudhary4799]

How to save it with which name

[@dharshinimagesh9591]

hi mam, pl write this example with while loop . i hav tried many times but always stuck wit where to give the increment "i=i+1" operator .

[@AmulsAcademy]

num = int(input(":")) if num > 1: i = 2 while i < num: if (num % i) == 0: print(num,"is not a prime number") break i =i+1 else: print(num,"is a prime number") else: print(num,"is not a prime number") :)

[@dharshinimagesh9591]

@@AmulsAcademy thank u very much . can u pl tel me wats wrong in this code n if possible could u correct it ?

[@dharshinimagesh9591]

lower=int(input("lower no ")) upper=int(input("upper no ")) i = 2 for num in range (upper,lower+1): while i < num: if (num % i) == 0: print(num,"is not a prime number") break i =i+1 else: print(num,"is a prime number") i want to print prime no's in the intervals like this, without two for loops ..

[@AmulsAcademy]

lower=int(input("lower no ")) upper=int(input("upper no ")) for num in range (lower,upper+1): i=2 while i < num: if (num % i) == 0: #print(num) print(num,"is not a prime number") break i =i+1 else: print(num,"is a prime number") Try this :)

[@dharshinimagesh9591]

​@@AmulsAcademy thank u very much mam . I've identified my mistake 🙏 u dont believe me , i have been fighting with this prime no's prg for past TEN days and I've found ur videos accidentally and i havnt expected this much response from u . u r really a respectful and a responsible teacher .🙏

[@TJ-wo1xt]

nice one.

[@shivprakashyadav3814]

why else is used for for loop not for if

[@AmulsAcademy]

We can use else case with loops :)

[@totansarker5460]

wow.. thank you very much.

[@AmulsAcademy]

You are most welcome :)

[@varshacm1444]

Mam why else is straight under for loop it should be under if know mam plse do reply mam

[@AmulsAcademy]

We can use else case with loops also. Here we want else part with for loop. The else block just after for/while is executed only when the loop is NOT terminated by a break statement.

[@bhavithasulax.]

Mam how can we print those prime numbers

[@trundlingwithjoy2237]

maam but if we put 9 it is showing that it is a prime number but as we know that it is not a prime number.....maam how to solve this problem?/

[@AmulsAcademy]

Give me the program 😊

[@mika4444]

how to check the number is a prime number in a range entered by the user????

[@AmulsAcademy]

Give me an example :)

[@mika4444]

@@AmulsAcademy for example...user enters the starting range and ending range...from that range we have to find which numbers are prime numbers.

[@ashishsinha5015]

mam why you have used else with for loop but not with if

[@AmulsAcademy]

else case can be used with loops also :) here we need else part with for loop :)

[@Balustatus]

tq

[@pravaalc8409]

Nicely explained, but if i enter number as 2, the code does not execute. please help

[@AmulsAcademy]

Thank you :) No it will work properly for input 2.

[@pravaalc8409]

@@AmulsAcademy thank you. noticed indentation was not properly placed in my code

[@AmulsAcademy]

Yes indentation matters a lot in python :)

[@anshumanchoudhary2658]

a=int(input("enter:")) if (a%2==0) or (a%3==0): print("it is not prime number") else: print("it is prime") this is write or wrong

[@pillarikala266]

Plz tell with while loop

[@hetanshikothari4177]

Here i got stuck with case number =2 here 2 modulo 2 will be 0 still it prints 2 is a prime number how does that work

[@AmulsAcademy]

in the for loop we took range from 0 to num when num=2 range becomes 2 to 2 range(2,2) so it won't execute for loop body :) You can execute this and check for i in range(2,2): print("hello") else: print("hi")

[@hetanshikothari4177]

Amulya's Academy thank you so much for the explanation!! Got it

[@umairgillani699]

how about if we want to check the list of prime numbers in a range x to y, where x and y could be any range..

[@AmulsAcademy]

I did make a video on how to print prime numbers in particular range please check that :)

[@umairgillani699]

@@AmulsAcademy Yes watched it. It makes a good logic. Please come up with more videos like these :)

[@crewmate3031]

Mam why did u use break. Can u tell me the use of it please 🙏🙏

[@AmulsAcademy]

if you want to exit from the loop then you can use break inside the loop. Execute the program without break you can see the difference :)

[@crewmate3031]

@@AmulsAcademy oo ok mam thanks

[@sandeepsinghnegi9220]

please help i am getting 55 as prime number. by writing below code. num= int(input("enter any number")) for i in range(2, num): if (num % i) == 0: print (num,' number is not prime') break else: print (num,' number is prime') break

[@AmulsAcademy]

num= int(input("enter any number")) for i in range(2, num): if (num % i) == 0: print (num,' number is not prime') break else: print (num,' number is prime') Now check whether it will give correct output or not :)

[@sandeepsinghnegi9220]

num = int(input("enter number to check prime number : .. ")) for i in range(2,num): if (num % i ) == 0: print (num,"not prime") break else: print(num,"number is prime")

[@muskaangupta4915]

% k bd wala else iff k indention m aan chahiy th na jo for k nicje ku aara

[@jeetgupta2286]

Thank u didi ❣️❣️🙏🙏

[@AmulsAcademy]

Most welcome 😊

[@ananddarshan1114]

then why the hell my program says 9 and 15 are prime number when i write the same program as yours.

[@asrithavardhini956]

by writing your code, for number 2 it is not showing anything..please help me

[@AmulsAcademy]

No it will print 2 is prime number. Give me the program i will check for you :)

[@asrithavardhini956]

Thanks:) it's working...👍😊

[@yadavj12]

Hello dear we have to find out a prime number or not means there is three conditions can you please explain those three conditions

[@aryavs4555]

may i give u a suggestion pls run the programme and show us the output it will ensure that ur codes are correct

[@AmulsAcademy]

Thank you for the suggestion:) Didn't i show the output in this video? Usually i do execute my program. :)

[@zizo8737]

Arya V S Watch the video properly she has shown the execution

[@uk0707raptor]

Mam this code is not working for number 2.

[@Engineer9060]

wrong concept .plz correct it acc to uyou when i will take 21 as ainput it will show it is prime no. as 21%2==1 but 21 is not a prime nno. ur soln is for even no.

[@gowthamselvaraj7793]

Please explain Circular prime number in python mam

[@bibekanandasahoo3497]

How I write this code in list comprehension method

[@urvi23]

Mam if we check no 2 how it will work?

[@seaofplatitudes780]

I was wondering the same thing.

[@smartcat5989]

mam do you teach in valia ?

[@byjusCOM-pw7xn]

Ur range function is not working may I know the reason

[@anusmitasamanta2608]

amazing ...

[@AmulsAcademy]

Thank you :)

[@0SIGMA]

TYSM!!

[@AmulsAcademy]

Pleasure :)

[@swatimaskawade5321]

can't we add int in the input statement ?🤔🤔🤔🤔🤔🤔

[@ramurachineni2255]

How to do same program with while loop

[@ajithkumarm9446]

Mam, why are u using for loop for all program?

[@AmulsAcademy]

If you want you can use while loop also. :)

[@munshidrahman630]

Tnq

[@ViralFeedTv]

WOW, tysm :D

[@nabeelmalik.4714]

If we use negative value then error occur...

[@prasanthkrishnam62]

How to get a preceding number of a given number

[@AmulsAcademy]

input-1 :)

[@vickykolle8821]

Wt happend if we not type a break

[@AmulsAcademy]

you won't get proper output:) When we get divisor of given number then we know that number is not prime so we need to come out of the loop that's why we used break :)

[@kairu9373]

Even or Odd and Prime or Composite numbers are different programming logics. What you are trying to imply in here is that every number divisible by 2 is not a Prime number when 9, 15, 21 and so on are not Prime numbers and are not divisible by 2. This is unclear and confusing. The way the tutorial is being discussed has never changed and is still the same as other content creators stating they found the answer behind Prime number logics.

[@Engineer9060]

you are the only one in the comment whom i found have some knowledge, other than people here are saying they are clear , its just a soln for even no. not for prime no.

[@KimTae47016]

I was also confused that by using this method it will print prime statements even for odd numbers..

[@itzboyon6983]

but if i input 2 it comes out nothing, i know it is a prime number

[@rahuljuneja1185]

According to your code,it starts dividing by 2. So,2%2==0 Then according to your code,2 should not be a prime number

[@AmulsAcademy]

No because in the for loop range will become 2 to 2 at that time . so it won't execute for loop directly goes to else part :)

[@rahuljuneja1185]

Amuls Academy Thanks.

[@rohitjoshi1777]

@@AmulsAcademy Did not understood range become 2 to 2 at that time

[@kryptonboron6104]

Mam...it is not working for *21* . What to do? But thanks for the video mam

[@AmulsAcademy]

21 is not prime number right ? What is the problem ? :)

[@kryptonboron6104]

Mam....When I entered 21, then it checks and says that *21 is prime* . Then I again tried designing a new code for it. Thanks for your reply mam😄

[@kratishrivastava6984]

plz tell me if num = 2

[@AmulsAcademy]

2 is a prime number:)

[@babusingh7837]

there is some mistake in your code see carefully

[@kumarisonali2553]

yes 2 is the smallest prime no.

[@vasudevareddy6749]

@@kumarisonali2553 ,code is working fine,give lower bound as 2,then it will print including with 2

[@Unidentifying]

How to do this without using break ?

[@djquick]

*remainder

[@manuaugustine750]

try 15 and see what output you will get

[@AmulsAcademy]

15 is not prime number :)

[@addictedroaster1573]

Instead of this large code.. We can do.. Num modulus 2 Or 3....remainder not eaual to 0 then it's PRIME NUMBER

[@AmulsAcademy]

That’s what we are doing here 😊

[@addictedroaster1573]

@@AmulsAcademy please make video on python interview programming question.. But not mcq... Something like paragraph narrated question.... Need it because I am final year student.. Please

[@Engineer9060]

@@AmulsAcademy sry but i thinks its a wrong code bcz for 21,9 it will show prime.

[@RK-jv3kw]

Are u from tamil nadu ? i understood well thanks for the video

[@AmulsAcademy]

No I am from Karnataka. Thank you :)

[@RK-jv3kw]

@@AmulsAcademy i am from kerala, i can easly recognise south indains

[@AmulsAcademy]

Hello :)

[@RK-jv3kw]

@@AmulsAcademy hello

[@RK-jv3kw]

you are nice teacher

[@SevenStepsAhead]

its remainder not reminder lmao

[@nagarani.g1694]

plese insert by with alagorithm

[@ryder3099]

One correction it is remainder not reminder

[@bunnysunil]

Madam I following your classes daily I am big fan of u yesterday I attended one interview I passed written test In second round they conducted system test But they gave to me a difficult task That task name is FLAMES I HOPE YOU KNOW THAT FLAMES CONCEPT before he conduct the system test He explained to me that FLAMES Take two persons name Cancel that common letters Count the remaining Letters For example total remaining letters are:(5) How to get this out put By using ptython code Plz explain this out madam

[@AmulsAcademy]

Try this: str1 = input("name1:") str2 = input("name2:") for i in str1: for j in str2: if i==j: str1=str1.replace(i,"",1) str2=str2.replace(i,"",1) print(i,j) print(str1,str2) print("remaining characters in str1:",len(str1)) print("remaining characters in str2:",len(str2)) :)

[@bloodbath8804]

while True: print(" thankyou very much")

[@AmulsAcademy]

Welcome :)

[@r4d1calwr4th7]

try 15 it is showing a prime no.

[@AmulsAcademy]

No it won't print 15 as prime number :)