Prime Number or Not

This program checks a number is mathematically prime or not. It is a optimize program to check a number is prime number or not.

# Program to check a number is prime or not.

n = eval(input("Enter Number:"))

flag = 0

if n ==2 :

flag = 1

elif n > 2 :

i = 2

while i > n :

if n%i == 0 :

flag = 1

break

else :

flag = 0

i += 1

else :

flag = 0

if flag == 0 :

print(n,"is a prime number.")

else :

print(n,"is not a prime number.")