data/problems/211.yml
---
:id: 211
:name: Divisor Square Sum
:url: https://projecteuler.net/problem=211
:content: |+
For a positive integer <var>n</var>, let σ<sub>2</sub>(<var>n</var>) be the sum of the squares of its divisors. For example,
σ<sub>2</sub>(10) = 1 + 4 + 25 + 100 = 130.
Find the sum of all <var>n</var>, 0 \< <var>n</var> \< 64,000,000 such that σ<sub>2</sub>(<var>n</var>) is a perfect square.