Definition of amicable numbers in English:
A pair of numbers, each of which is the sum of the factors of the other (e.g. 220 and 284).
- The Pythagoreans were also interested in what we now call amicable numbers - pairs in which each number is the sum of the proper divisors of the other.
- One particular interest involved what we now call amicable numbers.
- Today, the tally of known amicable numbers has grown to about two and half million.