P429
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Sum of Squares of Unitary Divisors

ℹ️Published on Sunday, 26th May 2013, 04:00 am; Solved by 2796;
Difficulty rating: 20%

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.



Soluzione

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