A positive integer greater than 1 which has no other factors

except 1 and therefore the number itself is named a prime number.

2, 3, 5, 7 etc. are prime numbers as they are doing not have the

other factors. But 6 isn’t prime (it is composite) since, 2 x 3 = 6.

num = 407

# take input from the user

# num = int(input(“Enter a number: “))

# prime numbers are greater than 1

if num > 1:

# check for factors

for i in range(2,num):

if (num % i) == 0:

print(num,”is not a prime number”)

print(i,”times”,num//i,”is”,num)

break

else:

print(num,”is a prime number”)

# if input number is less than

# or adequate to 1, it’s not prime

else:

print (num,”is not a prime number”)

11 times 37 is 407

In this program, variable num is checked if it's prime or not. Numbers but or adequate 
to 1 aren't prime numbers. Hence, we only proceed if the num is bigger than 1.

We check if num is strictly divisible by any number from 2 to num - 1. If we discover 
an element therein range, the amount isn't prime. Else the number is prime.

We can decrease the range of numbers where we glance for factors.

In the above program, our search range is from 2 to num - 1.

We could have used the range, [2, num / 2] or [2, num ** 0.5]. The later range is predicated 
on the very fact that a number must have an element but root of that number; 
otherwise the amount is prime.

You can change the worth of variable num within the above ASCII text file and test 
for other integers (if you want).