Множители

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
    char factors[100];
    int n, i, d, prev;
 
    printf("enter N:\n");
    scanf("%d", &n);
 
    /* finding a single-digit factors of the number */
    for (i = 0; n != 1; i++) {
        prev = n;
        for (d = 9; d > 0; d--)
            if (n % d == 0) {
                n /= d;
                factors[i] = d + '0';
                break;
            }
        if (n == prev) { 
            /* the remaining number is 
               a prime and not a single-digit one */
            printf("such number does not exist!\n");
            return 0;
        }
    }
    factors[i] = '\0';
 
    printf("the number, the product of digits"
        " of which is N, is %d\n", atoi(factors));
    return 0;
}