Python program to check if a number is Prime or not

ProgrammingPythonServer Side Programming

A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. Any whole number which is greater than 1 and has only two factors that is 1 and the number itself, is called a prime number

Let’s say the following is our input −

7

The output should be as follows −

Prime Number

Check if a number is Prime or not

Let us check if a number if a Prime number or not using the for loop −

Example

# Number to be checked for prime n = 5 # Check if the number is greater than 1 if n > 1: for i in range(2, int(n/2)+1): if (n % i) == 0: print(num, "is not a prime number") break else: print(n, "is a prime number") # If the number is less than 1, its also not a prime number. else: print(n, "is not a prime number")

Output

5 is a prime number

Check if a number is Prime or not using sqrt()

Let us check if a number if a Prime number or not using the sqrt() method −

Example

from math import sqrt # Number to be checked for prime n = 9 flag = 0 if(n > 1): for k in range(2, int(sqrt(n)) + 1): if (n % k == 0): flag = 1 break if (flag == 0): print(n," is a Prime Number!") else: print(n," is Not a Prime Number!") else: print(n," is Not a Prime Number!")

Output

9 is Not a Prime Number!
raja
Updated on 11-Aug-2022 12:02:33

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