While loop logic clarification + harmonic series

This is my code for finding the sum of a harmonic series of 1/n. I want it to stop when the sum is greater than or equal to 15, but the code cannot run. Can anyone let me know what I'm doing wrong? It seems to follow the correct while loop structure. Thanks!

#include <iostream>

using namespace std;

int main ()
{
    int divisor = 1;
    int sum = 1;
    while ((sum <= 15) && (divisor >=1))
    {
        sum = sum + (1/divisor);
        divisor++;
    }
    cout << "You need " << divisor << " terms to get a sum <= 15" << endl;
    return 0;
}