Problem 211
04 October 2008
For a positive integer n, let σ2(n) be the sum of the squares of its divisors. For example,
σ2(10) = 1 + 4 + 25 + 100 = 130.
Find the sum of all n, 0 
n 64,000,000 such that σ2(n) is a perfect square.
For a positive integer n, let σ2(n) be the sum of the squares of its divisors. For example,
Find the sum of all n, 0 n 64,000,000 such that σ2(n) is a perfect square.