Numbers primes in the range

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <mpi.h>

/*******************************************
Method to verify if number is prime
********************************************/

#define MASTER 0

int is_prime(long num){
    long max_divisor, d;
    if(num<=1)
        return 0;
    else if(num>3){
        if(num%2==0)
            return 0;
        max_divisor = sqrt(num);
        for(d = 3; d<=max_divisor; d+=2){
            if(num%d==0) return 0;
        }
    }
    return 1;
}


/*******************************************
Main method
********************************************/

int main(int argc, char** argv)
{
    // proc
    int quant = 1000, // num
        i,
        localSum = 0,
        globalSum = 0, tmp;

    // comm
    int myrank, nprocs;

    // split
    int split,
        begin,
        end;

    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
    MPI_Comm_size(MPI_COMM_WORLD,&nprocs);

    // split tasks
    split = ceil((float)(quant)/nprocs);
    begin = split * myrank;
    end = split * (myrank+1);

    // if happen overflow
    if (end > quant)
        end = quant;

    for (i = begin; i < end; ++i)
    {
        if (is_prime(i))
            localSum++;
    }
    // receive all sums of others process
    if (myrank == MASTER){
        globalSum = localSum;
        for (i = 0; i < nprocs; ++i)
        {
            MPI_Recv(&tmp,1,MPI_INT,i,0,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
            globalSum += tmp;
        }
        printf("%d primes were found between %d and %d\n", globalSum, 0, quant);
    }
    // send the local sum to master process
    else{
        MPI_Send(&localSum,1,MPI_INT,MASTER,0,MPI_COMM_WORLD);
    }

    MPI_Finalize();
    return 0;
}