Project Euler

Problem #211

For a positive integer n, let σ_(2)(n) be the sum of the squares of its divisors. For example,

σ_(2)(10) = 1 + 4 + 25 + 100 = 130.

Find the sum of all n, 0 < n < 64,000,000 such that σ_(2)(n) is a perfect square.