diff --git a/system/CLI/CLI.php b/system/CLI/CLI.php
index 32411d507ebc..6903054af1ee 100644
--- a/system/CLI/CLI.php
+++ b/system/CLI/CLI.php
@@ -1068,7 +1068,7 @@ public static function table(array $tbody, array $thead = [])
 
             foreach ($tableRows[$row] as $col) {
                 // Sets the size of this column in the current row
-                $allColsLengths[$row][$column] = static::strlen($col);
+                $allColsLengths[$row][$column] = static::strlen((string) $col);
 
                 // If the current column does not have a value among the larger ones
                 // or the value of this is greater than the existing one
@@ -1088,7 +1088,7 @@ public static function table(array $tbody, array $thead = [])
             $column = 0;
 
             foreach ($tableRows[$row] as $col) {
-                $diff = $maxColsLengths[$column] - static::strlen($col);
+                $diff = $maxColsLengths[$column] - static::strlen((string) $col);
 
                 if ($diff !== 0) {
                     $tableRows[$row][$column] .= str_repeat(' ', $diff);
@@ -1108,7 +1108,7 @@ public static function table(array $tbody, array $thead = [])
                 $cols = '+';
 
                 foreach ($tableRows[$row] as $col) {
-                    $cols .= str_repeat('-', static::strlen($col) + 2) . '+';
+                    $cols .= str_repeat('-', static::strlen((string) $col) + 2) . '+';
                 }
                 $table .= $cols . PHP_EOL;
             }
diff --git a/system/Database/Query.php b/system/Database/Query.php
index 8bf03b32430e..ebd9c279bdef 100644
--- a/system/Database/Query.php
+++ b/system/Database/Query.php
@@ -359,7 +359,7 @@ protected function matchSimpleBinds(string $sql, array $binds, int $bindCount, i
                 $escapedValue = '(' . implode(',', $escapedValue) . ')';
             }
 
-            $sql = substr_replace($sql, $escapedValue, $matches[0][$c][1], $ml);
+            $sql = substr_replace($sql, (string) $escapedValue, $matches[0][$c][1], $ml);
         } while ($c !== 0);
 
         return $sql;
diff --git a/system/Format/XMLFormatter.php b/system/Format/XMLFormatter.php
index 3d0383cc3f13..c85eae5feffe 100644
--- a/system/Format/XMLFormatter.php
+++ b/system/Format/XMLFormatter.php
@@ -93,6 +93,8 @@ protected function normalizeXMLTag($key)
             '\\x{FDF0}-\\x{FFFD}\\x{10000}-\\x{EFFFF}';
         $validName = $startChar . '\\.\\d\\x{B7}\\x{300}-\\x{36F}\\x{203F}-\\x{2040}';
 
+        $key = (string) $key;
+
         $key = trim($key);
         $key = preg_replace("/[^{$validName}-]+/u", '', $key);
         $key = preg_replace("/^[^{$startChar}]+/u", 'item$0', $key);
diff --git a/system/Helpers/number_helper.php b/system/Helpers/number_helper.php
index 1220373329e2..d88d7b961f4c 100644
--- a/system/Helpers/number_helper.php
+++ b/system/Helpers/number_helper.php
@@ -26,7 +26,7 @@ function number_to_size($num, int $precision = 1, ?string $locale = null)
         // Strip any formatting & ensure numeric input
         try {
             // @phpstan-ignore-next-line
-            $num = 0 + str_replace(',', '', $num);
+            $num = 0 + str_replace(',', '', (string) $num);
         } catch (ErrorException $ee) {
             // Catch "Warning:  A non-numeric value encountered"
             return false;
diff --git a/tests/system/Commands/ClearDebugbarTest.php b/tests/system/Commands/ClearDebugbarTest.php
index c0b5681b7861..d55988996ee8 100644
--- a/tests/system/Commands/ClearDebugbarTest.php
+++ b/tests/system/Commands/ClearDebugbarTest.php
@@ -41,7 +41,7 @@ protected function createDummyDebugbarJson(): void
 
         // create 10 dummy debugbar json files
         for ($i = 0; $i < 10; $i++) {
-            $path = str_replace($time, $time - $i, $path);
+            $path = str_replace((string) $time, (string) ($time - $i), $path);
             file_put_contents($path, "{}\n");
 
             $time -= $i;