Write a program or function that finds the number of zeroes at the end of
n! in base 10, where
n is an input number (in any desired format).
It can be assumed that
n is a positive integer, meaning that
n! is also an integer. There are no zeroes after a decimal point in
n!. Also, it can be assumed that your programming language can handle the value of
1 ==> 0 5 ==> 1 100 ==> 24 666 ==> 165 2016 ==> 502 1234567891011121314151617181920 ==> 308641972752780328537904295461
This is code golf. Standard rules apply. The shortest code in bytes wins.