diff --git a/lib/danog/PrimeModule.php b/lib/danog/PrimeModule.php
index 85354ca..d16386d 100644
--- a/lib/danog/PrimeModule.php
+++ b/lib/danog/PrimeModule.php
@@ -218,8 +218,11 @@ class PrimeModule
         if ($res[0] == false) {
             return false;
         }
-        while (array_product($res) !== $what) {
-            $res[] = self::native_single_cpp($what / array_product($res));
+        while (($product = array_product($res)) !== $what) {
+            if ($product == 0) {
+                return false;
+            }
+            $res[] = self::native_single_cpp($what / $product);
         }
 
         return $res;
diff --git a/tests/testing.php b/tests/testing.php
index b0e4b64..0d08833 100755
--- a/tests/testing.php
+++ b/tests/testing.php
@@ -94,6 +94,7 @@ function gen_payload()
     return chr(10).str_repeat(chr(0), 8).\danog\PHP\Struct::pack('<q', (int) (time() << 32)).pack('VV', 20, 1615239032).random_string(16);
 }
 
+
 echo PHP_EOL.'----------- HUGE SEMIPRIME TESTS (100 semiprimes) ----------'.PHP_EOL;
 $GLOBALS['medium'] = ['python' => 0, 'python_alt' => 0, 'wolfram' => 0, 'native' => 0, 'native_cpp' => 0];
 $tg = fsockopen('tcp://149.154.167.51:443');
@@ -110,6 +111,7 @@ fclose($tg);
 foreach ($medium as $type => $total) {
     echo $type.': total time '.$total.', medium time '.($total / $tot).PHP_EOL;
 }
+
 echo PHP_EOL.'------------------- SMALL MULTIPLE FACTOR TESTS -------------------'.PHP_EOL;
 $GLOBALS['medium'] = ['python' => 0, 'python_alt' => 0, 'wolfram' => 0, 'native' => 0, 'native_cpp' => 0];