by Dinesh Thakur Category: Control Structures

A Perfect Number is sum of its positive divisors, excluding the number itself. The First Perfect number is 6, For example 6 is a perfect number as 1,2 and3 are its divisors and the sum of divisors= ( 1 + 2 + 3)  = 6.

Algorithm for Perfect Number Program:


step 1: Read num

step 2: Set b=1, s=0

step 3: Repeat through step-5 until (b < num)

step 4: If (num mod b) equals to 0 then s=s+b

step 5: b=b+1

step 6: If s equals to num then print “num is perfect”

Else print “num is not perfect”

Step 7: Exit


Here is the Java Example for Perfect Number Program:

import java.util.Scanner;

class PerfectNumber
    public static void main(String args[])
        Scanner sl=new Scanner(;
        System.out.println("Enter A Number");
        int num=sl.nextInt();
        int b=1, s=0;
        while(b<num )
            if(num%b == 0)
                s += b;
        if(s == num)
            System.out.println(num+" is a perfect number");
           System.out.println(num+" is not a perfect number");

Perfect Number Program in Java

About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.C.A, MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.

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