mathlib

8985e395 - feat(archive/100-theorems-list/70_perfect_numbers): Perfect Number Theorem, Direction 2 (#4621)

feat(archive/100-theorems-list/70_perfect_numbers): Perfect Number Theorem, Direction 2 (#4621) Adds a few extra lemmas about `divisors`, `proper_divisors` and sums of proper divisors Proves Euler's direction of the Perfect Number theorem, finishing Freek 70