24. Write a program to accept a number and check and display whether it is a Niven number or not. (Niven number number which is divisible by the sum of its digits).
Example:
Consider the number 126.
Sum of its digits is 1 + 2 + 6 = 9 and 126 is divisible by 9.

Program Title: Check Niven Number

Java

import java.util.Scanner;
 
public class NivenNumber {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter a number: ");
        int num = sc.nextInt();
        int temp = num;
 
        int sum = 0;
 
        // Calculate sum of digits
        while (temp != 0) {
            int digit = temp % 10;
            sum += digit;
            temp /= 10;
        }
 
        System.out.println("Sum of digits: " + sum);
 
        // Check divisibility
        if (num % sum == 0) {
            System.out.println(num + " is a Niven Number.");
        } else {
            System.out.println(num + " is NOT a Niven Number.");
        }
 
        sc.close();
    }
}

Output

Sample Input / Output 1:
Enter a number: 126
Sum of digits: 9
126 is a Niven Number.

Sample Input / Output 2:
Enter a number: 123
Sum of digits: 6
123 is NOT a Niven Number.

📝 Explanation

Niven Number: A number divisible by the sum of its digits.
num % sum_of_digits == 0
Extract digits using % 10 and sum them.
Check if num is divisible by sum.
Display result.