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 $$10! \mbox{ is } 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.$$
Find the sum of the digits in the number 100!
In [4]:
from math import factorial
print( sum(int(i) for i in str(factorial(100))))