## 507. 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 = 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`

## Rust Solution

``````struct Solution;

impl Solution {
fn check_perfect_number(num: i32) -> bool {
if num == 1 {
return false;
}
let mut i = 2;
let mut sum = 1;
while i * i <= num {
if num % i == 0 {
sum += i;
sum += num / i;
}
i += 1;
}
sum == num
}
}

#[test]
fn test() {
assert_eq!(Solution::check_perfect_number(28), true);
}
``````

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