Krishnamurthy Number in Java

In Java, the Krishnamurthy number, also known as a Strong number, is a special type of number. It is defined as a number whose sum of the factorials of its digits is equal to the number itself. Similar to Prime and Armstrong numbers, Krishnamurthy numbers are often featured in interviews as Strong numbers.

To determine whether a number is a Krishnamurthy number, the following steps can be followed:

1. Take a number as input.
2. Calculate the factorial of each digit in the number.
3. Sum up the factorials of all the digits and store the result in a separate variable.
4. Compare the sum of the factorials with the original number.
5. If the sum of the factorials is equal to the original number, then the number is considered a Krishnamurthy number.

Example:

Number = 145  
= 1! + 4! + 5!  
= 1 + ( 4 * 3 * 2 * 1 ) + ( 5 * 4 * 3 * 2 * 1 )  
= 1 + 24 + 120  
= 145

KrishnamurthyNumber.java

//import required classes and packages  
import Java.util.*;   
import java.io.*;   
import java.util.Scanner;  
  
//create KrishnamurthyNumber class to check whether the given number is a Krishnamurthy number or not  
class KrishnamurthyNumber {   
      
    // create fact() method to calculate the factorial of the number   
    static int fact(int number)   
    {   
        int f = 1;   
        while (number != 0) {   
            f = f * number;   
            number--;   
        }   
        return f;   
    }   
  
    // create checkNumber() method that returns true when it founds number krishnamurthy   
    static boolean checkNumber(int number)   
    {   
        int sum = 0;    //initialize sum to 0   
          
        int tempNumber = number;    //create a copy of the original number   
          
        //perform operation until tempNumber will not equal to 0  
        while (tempNumber != 0) {   
            // calculate the factorial of the last digit of the tempNumber and then add it to the sum  
            sum = sum + fact(tempNumber % 10);   
  
            // replace the value of tempNumber by tempNumber/10   
            tempNumber = tempNumber / 10;   
        }   
  
        // Check whether the number is equal to the sum or not. If both are equal, number is krishnamurthy number  
        if(sum == number)  
            return true;  
        else  
            return false;  
    }   
  
    // main() method start  
    public static void main(String[] args)   
    {   
        int n;  //initialize variable n  
          
        //create scanner class object to read data from user  
        Scanner sc = new Scanner(System.in);  
          
        //custom message  
        System.out.println("Enter any number:");  
          
        //store user entered value into variable n  
        n = sc.nextInt();  
         
        if (checkNumber(n))   
            System.out.println(n + " is a krishnamurthy number");   
        else  
            System.out.println(n + "is not a krishnamurthy number");   
    }   
}

Output

FindAllKrishnamurthyNumber.java

//import required classes and packages  
import java.util.*;   
import java.io.*;   
import java.util.Scanner;  
  
//create FindAllKrishnamurthyNumber class to get all the Krishnamurthy number in a given range  
class FindAllKrishnamurthyNumber  
{  
    //main() method start  
    public static void main(String args[])  
    {  
        int range;  
          
        //create scanner class object  
        Scanner sc=new Scanner(System.in);  
          
        //show custom message  
        System.out.println("Enter the value of range");  
          
        //store user entered value into variable range  
        range = sc.nextInt();  
  
        for(int i = 1; i <= range; i++)  
            checkNumber(i);  
    }  
  
    // create fact() method to calculate the factorial of the number   
    static int fact(int number)   
    {   
        int f = 1;   
        while (number != 0) {   
            f = f * number;   
            number--;   
        }   
        return f;   
    }   
  
    // create checkNumber() method to check krishnamurthy number  
    static void checkNumber(int number)   
    {   
        int sum = 0;    //initialize sum to 0   
          
        int tempNumber = number;    //create a copy of the original number   
          
        //perform operation until tempNumber will not equal to 0  
        while (tempNumber != 0) {   
            // calculate the factorial of the last digit of the tempNumber and then add it to the sum  
            sum = sum + fact(tempNumber % 10);   
  
            // replace the value of tempNumber by tempNumber/10   
            tempNumber = tempNumber / 10;   
        }   
  
        // Check whether the number is equal to the sum or not. If both are equal, the number is Krishnamurthy number  
        if(sum == number)  
            System.out.println(number + " is a krishnamurthy number");   
    }  
}

Output

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