UVa 10235 - Simply Emirp

#include<bits/stdc++.h>
#define ll long long

using namespace std;

bool isPrime(ll n)
{
 ll d= sqrt(n);
 for(ll i=2; i<=d; i++)
 {
  if(n%i==0) return false;
 }
 return true;
}
int main()
{
 ll n;
 bool b,c;

 while(cin>>n)
 {
   b=false;
   c=false;
 
  b=isPrime(n);
  
  if(b)
  {
   ll rn =0;
            for(ll i =n;i!=0;i=i/10){
                rn = rn*10+i%10;
    }
    
   c= isPrime(rn);
   
   if(c && rn!=n) cout<<n<<" is emirp."<<endl;
   else cout<<n<<" is prime."<<endl;
  }
  
  else cout<<n<<" is not prime."<<endl;
 }
}