#Use math.factorial function

#import the math module
import math

#Use the factorial function
print(math.factorial(5))

The math.factorial() function is used to calculate the factorial of a given number. The factorial of a number n  is written as n! and is equal to the product of all positive integers less than or equal to n. For example the factorial of 5 is 120, because 5 x 4 x 3 x 2 x 1 = 120.

math.factorial(n)

Where, parameter n is an non-negative integer whose factorial is to be calculated. 

import math

math.factorial(0)
//1
math.factorial(1)
//1
math.factorial(3)
//6
math.factorial(4)
//24
math.factorial(5)
//120
math.factorial(7)
//5040
math.factorial(11)
//39916800
math.factorial(20)
//2432902008176640000

If n is not a non integer, a TypeError is raised. Whereas, if n is a negative number, a ValueError is raised.

import math 

math.factorial(5.5)
import math

math.factorial(-5)