Armstrong - Prime - Perfect

import java.io.*;
class arm
{
public static void main(String args[])throws IOException
{
DataInputStream in=new DataInputStream(System.in);
int no;
int r,n1,i,n,j,flag=0;
System.out.println("Enter a number: ");
no=Integer.parseInt(in.readLine());

System.out.println("");

//armstrong

n1=no;
int s=0;
while(n1>0)
{
r=n1%10;
s=s+(r*r*r);
n1=n1/10;
}
if(s==no)
{
System.out.println(s+" is armstrong");
}

System.out.println("");
System.out.println("");

//prime

n1=no;
for(j=2;j<=n1-1;j++)
{
if(n1%j==0)
{
flag=1;
break;
}
else
{
flag=0;
}
}
if(flag==0)
System.out.println(n1+"prime");

System.out.println("");
System.out.println("");

//perfect

n1=no;
int s1=0;
for(j=1;j<=n1-1;j++)
{
if(n1%j==0)
s1=s1+j;
}
if(s1==n1)
System.out.println(s1+"perfect");

}
};