## Factorial trailing digits 2

### Problem 592

For any `N`, let `f`(`N`) be the last twelve hexadecimal digits before the trailing zeroes in `N`!.

For example, the hexadecimal representation of 20! is 21C3677C82B40000,

so `f`(20) is the digit sequence 21C3677C82B4.

Find `f`(20!). Give your answer as twelve hexadecimal digits, using uppercase for the digits A to F.