Spy Number in Java

A Spy Number is a special number where the sum of its digits is equal to the product of its digits. These numbers are popular in Java programs, coding assignments, and logic-building practice.

What is a Spy Number?

A number is called a Spy Number if:

Examples

• 112
  Digits → 1, 1, 2
  Sum = 1 + 1 + 2 = 4
  Product = 1 × 1 × 2 = 2
  ❌ Not a Spy Number
• 123
  Digits → 1, 2, 3
  Sum = 1 + 2 + 3 = 6
  Product = 1 × 2 × 3 = 6
  ✔️ Spy Number
• 22
  Digits → 2, 2
  Sum = 2 + 2 = 4
  Product = 2 × 2 = 4
  ✔️ Spy Number

Java Program to Check Spy Number

Steps used in this Java program:

1. Extract each digit
2. Calculate digit sum
3. Calculate digit product
4. Compare both values

public class SpyNumber {

    public static void main(String[] args) {
        int num = 123; // Change this number to test others
        int temp = num;

        int sum = 0;
        int product = 1;

        while (temp > 0) {
            int digit = temp % 10;
            sum += digit;
            product *= digit;
            temp /= 10;
        }

        if (sum == product) {
            System.out.println(num + " is a Spy Number.");
        } else {
            System.out.println(num + " is NOT a Spy Number.");
        }
    }
}
    

Properties of Spy Numbers

• All single-digit numbers (0–9) are Spy Numbers.
• Spy Numbers depend entirely on digit operations.
• Most Spy Numbers have balanced digits like 22, 123, 132.

Practice Challenges