Let the divisors of n be d1, d2, ..., dk.
The geometric mean of the product of the divisors is
If n is not a square number, then the divisors can be organized into
pairs whose product is n
(e.g. the divisors of 12 are 1 and 12, 2 and 6, 3 and 4).
In this case, k is an even number, so let k = 2m.
Ordering the divisors into pairs, we can write the geometric mean as: