Problem 20 : Factorial digit sum

Problem Statement

n! means n × (n − 1) × … × 3 × 2 × 1

For example, 10! = 10 × 9 × … × 3 × 2 × 1 = 3628800, and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.

Find the sum of the digits in the number 100!

Solution

from math import factorial

a=list(str(factorial(100)))

sum=0
for i in a:
    sum+=int(i)

print(sum)

Output

648