If num <= 1, return false (no perfect numbers below 2).
Initialize sum = 1 (1 is always a proper divisor).
Loop i from 2 to √num. If num % i == 0, add i to sum. If i != num/i and num/i != num, add num/i to sum.
Return sum == num.
(Sum proper divisors)
If num <= 1, return false (no perfect numbers below 2).
Initialize sum = 1 (1 is always a proper divisor).
Loop i from 2 to √num. If num % i == 0, add i to sum. If i != num/i and num/i != num, add num/i to sum.
Return sum == num.