Perfect numbers are numbers in which you can add up all factors of said number (except for the number itself), and the sum of said factors will equal the number. For example, the factors of 6 are 1, 2, and 3 (excluding itself). 1+2+3=6, so 6 is a perfect number. 4 would not be a perfect number because the factors of 4 are 1 and 2 (excluding 4 itself). 1+2=3. 3 is not equal to 4, so 4 is not a perfect number.
Perfect numbers grow multi-exponentially. The first six perfect numbers are as follows: 6, 28, 496, 8128, 33550336, and 8589869056.
