Problem 20

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

def fact(n):
    if n > 1:
        return n*fact(n-1)
    else:
        return 1
        
print(sum([int(i) for i in str(fact(100))]))