Perfect number

 Perfect number
 --------------------

 In number theory, a perfect number is a positive integer that is equal
 to the sum of its positive divisors, excluding the number itself. 

 For instance, 6 has divisors 1, 2 and 3 (excluding itself), and 1 + 2 + 3 = 6,
 so 6 is a perfect number.

 Other perfect numbers are 28, 496, and 8,128.

//Source Code 
import java.util.Scanner;
 public class PerfectNumber
   {
       public static void main(String args[])
         {
             Scanner in=new Scanner(System.in);
             int num , sum =0,i;
             System.out.print("Enter a Number To Check : ");
             num = in.nextInt();
           
             for(i=1;i<=num/2;i++)
                {
                    if(num%i==0)
                       {
                           sum=sum+i;
                            }
                    }
                 
             if(sum==num)
                {
                    System.out.print("It is a Perfect Number . ");
                    }
             else
                {
                    System.out.print("It is Not a Perfect Number . ");
                    }
            }
        }
     
// Sample Input : 
   Enter a Number To Check : 6
// Sample Output:
  It is a Perfect Number .

// Sample Input : 
   Enter a Number To Check : 28
// Sample Output:
  It is a Perfect Number .

// Sample Input : 
   Enter a Number To Check : 10
// Sample Output:
  It is Not a Perfect Number .