Java: Check a number is a cyclic or not

Last update on March 11 2025 11:10:42 (UTC/GMT +8 hours)

Check Cyclic Number

Write a Java program to check if a number is cyclic or not.

A cyclic number is an integer in which cyclic permutations of the digits are successive multiples of the number. The most widely known is 142857:
142857 × 1 = 142857
142857 × 2 = 285714
142857 × 3 = 428571
142857 × 4 = 571428
142857 × 5 = 714285
142857 × 6 = 857142
Input Data:
Input a number: 142857

Pictorial Presentation:

Sample Solution:

Java Code:

import java.util.Scanner;
import java.math.BigInteger;
public class Example19 {

      public static void main( String args[] ){ 
            Scanner sc = new Scanner( System.in ); 
            System.out.print("Input a number: "); 
            String strnum = sc.nextLine().trim();
            BigInteger n = new BigInteger(strnum);
            int len = strnum.length()+1;
            String str = String.valueOf(len);
            BigInteger n1 = new BigInteger(str);
            StringBuilder buf = new StringBuilder();
            for(int i = 0 ; i < (len-1); i++) {
                buf.append('9');
            }
            BigInteger total = new BigInteger(buf.toString());
            if(n.multiply(n1).equals(total)) {
                System.out.println("It is a cyclic number.");
            }
            else {
                System.out.println("Not a cyclic number.");
            }                    
        }
    }

Sample Output:

Input a number: 142857                                                                                        
It is a cyclic number. 

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to check if a number is cyclic by generating all cyclic permutations and verifying their multiples.
• Write a Java program to determine cyclicity using string slicing and modular arithmetic on the number's digits.
• Write a Java program to recursively generate cyclic permutations and compare them with successive multiples.
• Write a Java program to filter cyclic numbers from a list by validating their rotation properties using streams.

Java Code Editor:

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