Smith Number: simple & Easy

Smith Number the sum of digits is equal to the sum of the digits of all its prime factors.
One example of it is 666.
As 666= 2 * 3 * 3 * 37
Since 6+6+6(sum of digits)=2 + 3 + 3 + (3+7)(sum of factors digits) = 18

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import java.io.*;
class SmithNumber
{
    static int s=0;
    public static int sumdig(int n)
    {
        if(n==0)
        {
            return 0;
        }
        else
        {
            int d=n%10;
            return(d+sumdig(n/10));
        }
    }
    static int sum=0;
    public static int prime_sum(int n,int i)
    {
        if(n>1)
        {
            if(n%i==0)
            {
                sum=sum+sumdig(i);
                return(prime_sum(n/i,i));
            }
            else
            {
                return(prime_sum(n,i+1));
            }
        }
        else
        {
            return sum;
        }
    }

    public static void main()throws IOException
    {
        System.out.println("Enter the number");
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int num=Integer.parseInt(br.readLine()); int res1=sumdig(num);
        int res2=prime_sum(num,2);
        if(res1==res2)
        {
            System.out.println("This number is smith");
        }
        else
        {
            System.out.println("NOT SMITH NUMBER");
        }
    }
}

Output:
Enter the number
666
This number is smith

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