Inconsitent behaviour with computation of "greatest product given 'n' adjacent digits" (D language)

I'm working on a solution for Project Euler (problem 8) which involves working out the largest product of thirteen adjacent digits. I wrote a solution (below) but it doesn't seem to be outputting the correct answer when the length of the slice is 13. It is correct when I set the length of adjacent digits to "4" but not "13". Can you help me find the error?

This was written in the D programming language:

/*
 * Project Euler: Classic, "Largest product in a series" solution
 * Implementation by A. S. "Aleksey" Ahmann <hackermaneia@riseup.net>
 * - https://github.com/Alekseyyy
 *
 * Problem link: https://projecteuler.net/problem=8
 */

import std.stdio : writeln;
import std.array : replace;
import std.conv : to;

string number = "73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450";

void main() {

    number = replace(number, "\n", "");
    int[] x = format_adjacent(number);
    int largest_product = largestProduct(x, 13);

    writeln(largest_product);
}

int[] format_adjacent(string number) {

    int[] adjacent_numbers;
    for (int i = 0; i < number.length; i++)
        adjacent_numbers ~= to!int(number[i] - to!char("0"));
    return adjacent_numbers;
}

int computeProduct(int[] sequence) {

    int product = sequence[0];
    for (int i = 1; i < sequence.length; i++)
        product = product * sequence[i];
    return product;
}

int largestProduct(int[] sequence, int slice) {

    int largest_product = 0;

    int n = 0;
    int fin = to!int(sequence.length) - (slice - 1);

    while (n < fin) {
        int[] seq = sequence[n .. n + slice];
        int product = computeProduct(seq);
        if (product > largest_product)
            largest_product = product;
        n = n + 1;
    }
    return largest_product;
}

How big is an int? I tried writing such a program in C using a 64 bit integer for the computed product and found that the largest for 13 characters was from the string 5576689664895 (with the 557 at the end of line 4 of your string) and the product was, in hex 0x57994b000 which doesn't fit in 32 bits.