#### 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

**Watch java videos**

```
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