Their sum is 1+2+3=6. This number is named a "perfect number", equal to sum of its proper divisors.

- Give the sum of the proper divisors of 600. Solution
- Find all other perfect numbers <100. Solution
- Two numbers such that the sum of aliquot parts of each one equals the other are said to be "amicable".

Find two amicable numbers <1000. Solution

Conversely, we might want to find a number, given the sum of its divisors.

- Find all numbers whose sum of all divisors equals 56. Solution

Scripts :

- sum of divisors