diff --git a/system/Helpers/number_helper.php b/system/Helpers/number_helper.php
index 96468ddcdea3..0999d200f99b 100644
--- a/system/Helpers/number_helper.php
+++ b/system/Helpers/number_helper.php
@@ -82,8 +82,9 @@ function number_to_amount($num, int $precision = 0, ?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) {
+            // Catch "Warning:  A non-numeric value encountered"
             return false;
         }
 
diff --git a/tests/system/Helpers/NumberHelperTest.php b/tests/system/Helpers/NumberHelperTest.php
index 9b3afa61992f..7e5fe2a358c4 100644
--- a/tests/system/Helpers/NumberHelperTest.php
+++ b/tests/system/Helpers/NumberHelperTest.php
@@ -38,6 +38,11 @@ public function testRomanNumber(): void
         $this->assertSame('X', number_to_roman(10));
     }
 
+    public function testRomanNumberString(): void
+    {
+        $this->assertSame('XCVI', number_to_roman('96'));
+    }
+
     public function testRomanNumberRange(): void
     {
         $this->assertNull(number_to_roman(-1));
@@ -70,6 +75,11 @@ public function testNumberToSize(): void
         $this->assertSame('456 Bytes', number_to_size(456, 1, 'en_US'));
     }
 
+    public function testNumberToSizeString(): void
+    {
+        $this->assertSame('456 Bytes', number_to_size('456', 1, 'en_US'));
+    }
+
     public function testKbFormat(): void
     {
         $this->assertSame('4.5 KB', number_to_size(4567, 1, 'en_US'));
@@ -109,6 +119,11 @@ public function testThousands(): void
         $this->assertSame('1,000 thousand', number_to_amount('999999', 0, 'en_US'));
     }
 
+    public function testThousandsInt(): void
+    {
+        $this->assertSame('123 thousand', number_to_amount(123000, 0, 'en_US'));
+    }
+
     public function testMillions(): void
     {
         $this->assertSame('123.4 million', number_to_amount('123,400,000', 1, 'en_US'));