In this post we'll see a Python program to check whether the passed number is a prime number or not. This program also shows a use case where
__for loop with else in Python__ can be used.

A number is a prime number if it can only be divided either by 1 or by the number itself. So the passed number has to be divided in a loop from 2 till number/2 to check if number is a prime number or not.

You need to start loop from 2 as every number will be divisible by 1.

You only need to run your loop till number/2, as no number is completely divisible by a number more than its half. Reducing the iteration to N/2 makes your program to display prime numbers more efficient.

### Check prime number or not Python program

def check_prime(num): for i in range(2, num//2+1): # if number is completely divisible then it # it is not a prime number so break out of loop if num % i == 0: print(num, 'is not a prime number') break # if loop runs completely that means a prime number else: print(num, 'is a prime number') check_prime(13) check_prime(12) check_prime(405) check_prime(101)

__Output__

13 is a prime number 12 is not a prime number 405 is not a prime number 101 is a prime number

That's all for this topic **Python Program to Check Prime Number**. If you have any doubt or any suggestions to make please drop a comment. Thanks!

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