What is an abundant number?

Answer 1

There are three equivalent definitions for an abundant number.

A number is abundant if:

1. the sum of all its factors (including itself) is more than double the number;
   
2. the sum of all factors of the number which are smaller than the number, must be more than the number;
   
3. the sum of all proper factors of the number must be at least as large as the number.

Answer 2

An abundant number is a number with its proper factors equalling a higher number than itself.