Write a program to input a number and check whether it is Mersenne Prime Number or not? (A number is said to be Mersenne prime number if it is Mersenne and Prime both.)

37)   Write a program to input a number and check whether it is Mersenne Prime Number or not? (A number is said to be   Mersenne prime number if it is Mersenne and Prime both.)

import java.util.*;

public class Mersenne_prime_6

{

   public static void main(String args[ ])

    {

        Scanner sc = new Scanner (System.in);

        System.out.println("Enter a number");

        int a = sc.nextInt();

        int c = 0;

        for(int i=1;i<=a;i++)

        {

            if(a%i==0)

            c++;

        }

        double p = a+1;

        while(p>1.0)

        {

            p=p/2.0;

        }

        if(p==1&&c==2)

        {

            System.out.println("Entered number is a MERSENNE PRIME");

        }

        else

        {

            System.out.println("Entered number is not a MERSENNE PRIME");

        }

    }

}