Perfect Numbers – Definition & Examples

Definition: 

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself.
For example 6 has 1, 2, and 3 divisors (excluding itself), and 1 + 2 + 3 = 6, so 6 is a perfect number.

28 has 1, 2, 4, 7, and 14 divisors (excluding itself), and 1 + 2 + 4 + 7 + 14 = 28, so 28 is a perfect number.

First ten perfect numbers:

6

28

496

8128

33550336

8589869056

137438691328

2305843008139952128

2658455991569831744654692615953842176

191561942608236107294793378084303638130997321548169216