```
public class Solution {
public boolean checkPerfectNumber(int num) {
if (num <= 1) return false;
int sum = 1;
for (int i = 2; i <= Math.sqrt(num); i++) {
if (num % i == 0){
sum += i;
if (i * i != num)
sum += num/i;
}
}
return sum == num;
}
}
```