素数回文问题

#include<bits/stdc++.h>
using namespace std;
typedef  long long  ll;
void solve(ll k)
{
    ll i;
    for ( i = 2; i <= sqrt(k); i++)
    {
        if (k % i == 0)
        {
            cout << "noprime";
            break;
        }
    }
    if (i > sqrt(k))
        cout << "prime";
}
int main()
{
    ll n;
    cin >> n;
    ll a, b=1;
    string n1 = to_string(n); //to_string函数可以将数字变为字符串
    n /= 10;
    while (b)
    {
        b = n / 10;
        a = n % 10;
        string z = to_string(a);
        n1 += z;
        n = b;
    }
    ll n2 = atoll(n1.c_str());  //atoll函数是将字符串变为长长整型

    solve(n2);

    return 0;
}