| Amicable numbers come in pairs in which each number is the sum of the proper divisors of the other. |
| An odd perfect number is defined to be an odd integer that is equal to the sum of its proper divisors. |
| A pair of amicable numbers is a pair like 220 and 284 such that the proper divisors of one number sum to the other and vice versa. |
| Chance of inserting hang folders wheel base 39-33, swing or lenghtwise divisors, rounded flank and top. |
| The Sainte-Laguë method uses divisors of 1, 3, 5, 7, etc, and was used in the 2009 European elections in Germany, Latvia and Sweden. |
| A number is abundant if the sum of its proper divisors is greater than the number itself. |
