# Tag Archives: perfect numbers

## Sums of reciprocals of divisors, perfect numbers

A perfect number is a positive integer $n$ such that $$\sum_{d|n} d = 2n.$$Put another way, $n$ is the sum of its proper divisors. Check out a a quick intro to perfect numbers that I wrote last November. The first three perfect numbers are $6, 28,$ and $496$. Currently, the largest perfect number, corresponding to […]