How to Check Perfect Number in Java Program

A perfect number is a positive integer where the sum of all its positive divisors, except itself, is equal to the number itself. For example 6 is a perfect number as 1,2 and3 are its divisors and the sum of divisors=1+2+3=6. Here we have created a program that will take the number from the user and reports whether it is perfect or not.

Here is the code:

import java.util.*;

public class PerfectNumber {
	public static void main(String[] args) {
		System.out.println("Enter any number");
		Scanner input = new Scanner(System.in);
		int num = input.nextInt();
		int perfectNo = 0;
		int i;
		System.out.println("Factors are:");
		for (i = 1; i < num; i++) {
			if (num % i == 0) {
				perfectNo += i;
				System.out.println(i);
			}
		}
		if (perfectNo == num) {
			System.out.println("number is a perfect number");
		} else {
			System.out.println("number is not a perfect number");
		}
	}
}

Output:

Enter any number
28
Factors are:
1
2
7
14
number is a perfect number

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