Why this code only runs on limited number of processors? - mpi

Question

I wrote this code to measure the time wall for MPI_Bcast(), but the code only runs on specific numbers of processors-8,16, 24, 32. I need it to be able to run for any number of processors and any size of array. There is an error with the segmentation that doesn't allow it to run for array size of 2^13 and bigger.
#include<mpi.h>
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main(int argc, char *argv[]){
MPI_Init(&argc, &argv);
int rank, size;
long int N = pow(2,12);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
long double start, end;
float* buffer = (float*)malloc(sizeof(float*) * N + 1);
if(rank == 0){
/*Creating data array of N random floating numbers*/
for(int i =0; i < N; i++){
buffer[i] = rand();
buffer[i]= buffer[i]/rand();
}
start = MPI_Wtime();
printf("Start Time:%Lf\nRoot processor-Rank %d- started broadcasting data buffer of %li floating numbers...\n", start, rank, N);
MPI_Bcast(buffer, N, MPI_FLOAT, 0,MPI_COMM_WORLD);
end = MPI_Wtime();
printf("Total time elapsed: %Lf\n", end - start);
}
if(rank != 0){
printf("Processor %d of %d processors, received the broadcast.\n", rank, size);
}
/*if(rank == 0){
end = MPI_Wtime();
printf("Total time elapsed: %Lf\n", end - start);}*/
MPI_Finalize();
}