Harshad (Or Niven) Number

An integer number in base 10 which is divisible by sum of it digits is said to be a Harshad Number. An n-harshad number is an integer number divisible by sum of its digit in base n.

Below are first few Harshad Numbers represented in base 10:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 18, 20………

Given a number in base 10, our task is to check if it is a Harshad Number or not.

Examples :

Input: 3
Output: 3 is a Harshad Number

Input: 18
Output: 18 is a Harshad Number

Input: 15
Output: 15 is not a Harshad Number

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

1. Extract all the digits from the number using % operator and calculate the sum.
2. Check if the number is divisible by sum.

Below is implementation of above idea:

C/C++

// C++ program to check if a number is Harshad 
// Number or not. 
#include <bits/stdc++.h> 
using namespace std; 
  
// function to check Harshad Number 
bool checkHarshad(int n) 
{ 
    // calculate sum of digits 
    int sum = 0; 
    for (int temp = n; temp > 0; temp /= 10) 
        sum += temp % 10; 
  
    // Return true if sum of digits is multiple 
    // of n 
    return (n % sum == 0); 
} 
  
// driver program to check above function 
int main() 
{ 
    checkHarshad(12) ? cout << "Yes\n" : cout << "No\n"; 
    checkHarshad(15) ? cout << "Yes\n" : cout << "No\n"; 
  
    return 0; 
} 

Java

// Java program to check if a number is Harshad 
// Number or not 
  
public class GFG { 
    // method to check Harshad Number 
    static boolean checkHarshad(int n) 
    { 
        // calculate sum of digits 
        int sum = 0; 
        for (int temp = n; temp > 0; temp /= 10) 
            sum += temp % 10; 
  
        // Return true if sum of digits is multiple 
        // of n 
        return (n % sum == 0); 
    } 
  
    // Driver program to test above functions 
    public static void main(String[] args) 
    { 
        System.out.println(checkHarshad(12) ? "Yes" : "No"); 
        System.out.println(checkHarshad(15) ? "Yes" : "No"); 
    } 
} 

Python

# Python program to check  
# if a number is Harshad  
# Number or not. 
  
def checkHarshad( n ) : 
    sum = 0
    temp = n 
    while temp > 0 : 
        sum = sum + temp % 10
        temp = temp / 10
    # Return true if sum of 
    # digits is multiple of n 
    return n % sum == 0
  
# Driver Code 
if(checkHarshad(12)) : print("Yes") 
else : print ("No") 
  
if (checkHarshad(15)) : print("Yes") 
else : print ("No") 
      
# This code is contributed 
# by Nikita Tiwari 

C#

// C# program to check if a number is Harshad 
// Number or not 
using System; 
  
public class GFG { 
  
    // method to check Harshad Number 
    static bool checkHarshad(int n) 
    { 
  
        // calculate sum of digits 
        int sum = 0; 
        for (int temp = n; temp > 0; temp /= 10) 
            sum += temp % 10; 
  
        // Return true if sum of digits is 
        // multiple of n 
        return (n % sum == 0); 
    } 
  
    // Driver program to test above functions 
    public static void Main() 
    { 
        Console.WriteLine(checkHarshad(12) ? "Yes" : "No"); 
  
        Console.WriteLine(checkHarshad(15) ? "Yes" : "No"); 
    } 
} 
  
// This code is contributed by vt_m. 

PHP

<?php 
// php program to check if  
// a number is Harshad  
// Number or not. 
  
// function to check  
// Harshad Number 
function checkHarshad($n) 
{ 
    // calculate sum of digits 
    $sum = 0; 
    for ($temp = $n; $temp > 0; 
                     $temp /= 10) 
        $sum += $temp % 10; 
  
    // Return true if sum of 
    // digits is multiple of n 
    return ($n % $sum == 0); 
} 
  
// Driver Code 
$k = checkHarshad(12) ? "Yes\n" : "No\n"; 
     echo($k); 
$k = checkHarshad(15) ? "Yes\n" : "No\n"; 
     echo($k); 
  
// This code is contributed by ajit. 
?> 

Output :

Yes
No

References:
https://en.wikipedia.org/wiki/Harshad_number

This article is contributed by Harsh Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

My Personal Notes