Perfect Number

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. A divisor of an integer x is an integer that can divide x evenly.

Given an integer n, return true if n is a perfect number, otherwise return false.

Example 1:

Input: num = 28
Output: true
Explanation: 28 = 1 + 2 + 4 + 7 + 14
1, 2, 4, 7, and 14 are all divisors of 28.

Example 2:

Input: num = 7
Output: false

Constraints:

• 1 <= num <= 108

SOLUTION:

class Solution:
    def getFactors(self, n, factors):
        for i in range(n - 1, 0, -1):
            if i not in factors and n % i == 0:
                factors.update({i})
                factors.update({n//i})
                self.getFactors(i, factors)

    def checkPerfectNumber(self, num: int) -> bool:
        fsum = 1
        i = 2
        while i * i <= num:
            if num % i == 0:
                fsum = fsum + i + num//i
            i += 1
        return (True if fsum == num and num!=1 else False)