Just the proper divisors of the number added together gives a number, and if the proper divisors of that number summed up is equal to the first number it's an amicable pair but only when the sum of the proper divisors is not the same as the first number(e.g. 6 has 1, 2, 3 as proper divisors, which summed up is 6, therefor it's a perfect number, not an amicable number)
