How to Print perfect number at least 6 in very quick time.

Question

Perfect number

Answer 1

public class Program
{
public static void main(String[] args) {
int n=28;
int sum=0;
int i=1;
while(i<=n/2)
{
if (n/i==0)
{
sum =sum+i;
}
i++;
}
if(sum==n)
{
System.out.println("perfect num"+n);}
else
System.out.println("not perfect no"+n);

}
}

Answer 2

modify it using
import java.util.Scanner();
and use for loop