0507. Perfect Number

https://leetcode.com/problems/perfect-number

Description

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 = 6
**Output:** true

Example 3:

**Input:** num = 496
**Output:** true

Example 4:

**Input:** num = 8128
**Output:** true

Example 5:

**Input:** num = 2
**Output:** false

Constraints:

• 1 <= num <= 108

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