Write a Python Program to Check Prime Number

A prime number is a number that is only divisible by 1 and itself.

In this tutorial, we will write a Python program to check whether a given number is prime or not.


To check whether a number is prime or not, we need to iterate through all the numbers from 2 to n-1, where n is the given number.

If we find any number between 2 and n-1 that divides n evenly, then the number is not prime.

If no number between 2 and n-1 divides n evenly, then the number is prime.

Let’s implement the above logic in Python:

def is_prime(n):
    if n < 2:
        return False
    for i in range(2, n):
        if n %% i == 0:
            return False
    return True

In the above code, we first check if the given number is less than 2.

If it is less than 2, then it is not a prime number, so we return False.

Otherwise, we iterate through all the numbers from 2 to n-1 using a for loop.

If any number between 2 and n-1 divides n evenly, then we return False.

If we iterate through all the numbers from 2 to n-1 and do not find any number that divides n evenly, then we return True, indicating that the number is prime.

Let’s test our function with a few examples:

print(is_prime(5))  # True
print(is_prime(10))  # False
print(is_prime(23))  # True
print(is_prime(1))  # False

In conclusion, we have written a simple Python program to check whether a given number is prime or not.

This program can be useful in many applications where prime numbers are required, such as cryptography or generating secure keys.