Thought Process

This problem is very similar to Problem 30, 9! = 362880 is the largest one digit can contribute => 8*9! = 2903040 is the largest possible number that can be the sum of the factorial of their digits because this is a 7 digit number.

I modified my Digit sum Function to return the factorial sum of digits

Simply loop through 3 to 2903040 and check digit_sum(x) is equal to x