Prime Number Program in Python

In this program, we are going to check whether the given number is prime or not by using python.

Prime number is a positive integer greater than 1 that has no positive integer divisors other than 1 and itself.

In other words, a prime number is a positive integer that is not divisible by any other positive integer except for 1 and itself.

Example-2,3,5,7 etc.

Algorithm:

• Prompt the user to enter a number.
• Store the number in a variable n.
• Check if n is less than or equal to 1. If it is, print The number is not prime and return from the function.
• Iterate over the range 2 to sqrt(n) (inclusive) using a for loop.
• Check if n is divisible by the current loop variable. If it is, print The number is not prime and return from the function.
• Print The number is prime after the for loop has completed.

Code:

n = int(input("Enter the number that has to be checked: "))
a = 0
for i in range(2, int(n / 2)):
    if n % i == 0:  // finding whether the number has a factor or not
        a = a + 1
if a > 0:
    print("The number is not prime")
else:
    print("The number is prime")

Output:

Enter the number that has to be checked:97
The number is prime

Enter the number that has to be checked: 54
The number is not prime