Question

Which of the following numbers is a perfect number?

(a) 4
(b) 12
(c) 8
(d) 6

Answer 1

(d) 6
A number for which the sum of all its factors is equal to twice the number is called a perfect number.
Factors of 6 are 1, 2 ,3, and 6.

Sum of the factors of 6 = 1 + 2 + 3 + 6 = 12 = 2 × 6
Hence, 6 is a perfect number.