Whole number for which the sum of its proper divisors is greater than the number itself.
All whole numbers can be classified in one of these three classes:
- Abundant numbers,
- Perfect numbers,
- Deficient numbers.
Examples
- Consider the whole number 20.
The sum of its proper divisors is 22, like this: 1 + 2 + 4 + 5 + 10 = 22.
Because 22 > 20, this means that 20 is an abundant number. - Consider the number 81.
The sum of its proper divisors is 40: 1 + 3 + 9 + 27 = 40.
Because 40 < 81, this means that 81 is not an abundant number.