A unitary divisor d of a number n is a divisor of n that has the property gcd(d,n/d)=1. The unitary divisors of 4!=24 are 1,3,8 and 24. The sum of their squares is 12+32+82+242=650.
Let S(n) represent the sum of the squares of the unitary divisors of n. Thus S(4!)=650.
Find S(100000000!) modulo 1000000009.