Perfect Numbers

What is a perfect number?
A perfect number is a whole number, an integer greater than zero; and
when you add up all of the factors less than that number, you get that number.
Examples:
The factors of 6 are 1, 2, 3 and 6.1 + 2 + 3 = 6
The factors of 28 are 1, 2, 4, 7, 14 and 28.1 + 2 + 4 + 7 + 14 = 28
The factors of 496 are 1, 2, 4, 8, 16, 31, 62, 124, 248 and 496.1 + 2 + 4 + 8 + 16 + 31 + 62 + 124 + 248 = 496
The factors of 8128 are 1, 2, 4, 8, 16, 32, 64, 127, 254, 508, 1016, 2032, 4064 and 8128. I'll let you add them up.