diff --git a/core/database.php b/core/database.php
index 3bead690..bc002bcb 100644
--- a/core/database.php
+++ b/core/database.php
@@ -213,7 +213,7 @@ class Database
             // $stmt = $this->db->prepare($query);
             if (!array_key_exists(0, $args)) {
                 foreach ($args as $name=>$value) {
-                    if (is_numeric($value)) {
+                    if (is_int($value)) {
                         $stmt->bindValue(':'.$name, $value, PDO::PARAM_INT);
                     } else {
                         $stmt->bindValue(':'.$name, $value, PDO::PARAM_STR);
diff --git a/core/imageboard/image.php b/core/imageboard/image.php
index 33804a60..c757e334 100644
--- a/core/imageboard/image.php
+++ b/core/imageboard/image.php
@@ -81,9 +81,9 @@ class Image
             }
             $this->locked = bool_escape($this->locked);
 
-            assert(is_numeric($this->id));
-            assert(is_numeric($this->height));
-            assert(is_numeric($this->width));
+            assert(is_int($this->id));
+            assert(is_int($this->height));
+            assert(is_int($this->width));
         }
     }
 
diff --git a/core/polyfills.php b/core/polyfills.php
index c39ec13a..4f0b2c71 100644
--- a/core/polyfills.php
+++ b/core/polyfills.php
@@ -503,7 +503,7 @@ function bool_escape($input): bool
     */
     if (is_bool($input)) {
         return $input;
-    } elseif (is_numeric($input)) {
+    } elseif (is_int($input)) {
         return ($input === 1);
     } else {
         $value = filter_var($input, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);