find the thirteen adjacent digits in the 1000-digit number that have the greatest product. what is the value of this product? in php

main.php
$num = "73167176531330624919225119674426574742355349194934"
     ."96983520312774506326239578318016984801869478851843"
     ."85861560789112949495459501737958331952853208805511"
     ."12540698747158523863050715693290963295227443043557"
     ."66896648950445244523161731856403098711121722383113"
     ."62229893423380308135336276614282806444486645238749"
     ."30358907296290491560440772390713810515859307960866"
     ."70172427121883998797908792274921901699720888093776"
     ."65727333001053367881220235421809751254540594752243"
     ."52584907711670556013604839586446706324415722155397"
     ."53697817977846174064955149290862569321978468622482"
     ."83972241375657056057490261407972968652414535100474"
     ."82166370484403199890008895243450658541227588666881"
     ."16427171479924442928230863465674813919123162824586"
     ."17866458359124566529476545682848912883142607690042"
     ."24219022671055626321111109370544217506941658960408"
     ."07198403850962455444362981230987879927244284909188"
     ."84580156166097919133875499200524063689912560717606"
     ."05886116467109405077541002256983155200055935729725"
     ."71636269561882670428252483600823257530420752963450";

$adjacentDigits = 13;

$products = []; // Initialize an empty array to hold products

for ($i = 0; $i < strlen($num) - $adjacentDigits; $i++) {
    $product = 1; // Initialize product as 1
    $tempArr = str_split(substr($num, $i, $adjacentDigits)); // Create an array of the current $adjacentDigits
    foreach ($tempArr as $digit) {
        $product *= $digit; // Multiply each digit to the product
    }
    array_push($products, $product); // Add product to the products array
}

echo max($products); // Print the maximum value in $products
1728 chars
36 lines

main.php
23514624000
12 chars
2 lines