diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 2a60d86ab5..aa7402313d 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -60,11 +60,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Calculation/DateTimeExcel/Helpers.php
 
-		-
-			message: "#^Binary operation \"%%\" between string and 24 results in an error\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php
-
 		-
 			message: "#^Binary operation \"\\-\" between 1 and array\\|float\\|string results in an error\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php b/src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php
index 78d67b837d..bf8114756d 100644
--- a/src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php
+++ b/src/PhpSpreadsheet/Calculation/DateTimeExcel/TimeValue.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
 
+use Composer\Pcre\Preg;
 use Datetime;
 use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
 use PhpOffice\PhpSpreadsheet\Calculation\Functions;
@@ -12,6 +13,19 @@ class TimeValue
 {
     use ArrayEnabled;
 
+    private const EXTRACT_TIME = '/\b'
+        . '(\d+)' // match[1] - hour
+        . '(:' // start of match[2] (rest of string) - colon
+        . '(\d+' // start of match[3] - minute
+        . '(:\d+' // start of match[4] - colon and seconds
+        . '([.]\d+)?' // match[5] - optional decimal point followed by fractional seconds
+        . ')?' // end of match[4], which is optional
+        . ')' // end of match 3
+        // Excel does not require 'm' to trail 'a' or 'p'; Php does
+        . '(\s*(a|p))?' // match[6] optional whitespace followed by optional match[7] a or p
+        . ')' // end of match[2]
+        . '/i';
+
     /**
      * TIMEVALUE.
      *
@@ -48,12 +62,15 @@ public static function fromString($timeValue)
         }
 
         $timeValue = trim($timeValue ?? '', '"');
-        $timeValue = str_replace(['/', '.'], '-', $timeValue);
-
-        $arraySplit = preg_split('/[\/:\-\s]/', $timeValue) ?: [];
-        if ((count($arraySplit) == 2 || count($arraySplit) == 3) && $arraySplit[0] > 24) {
-            $arraySplit[0] = ($arraySplit[0] % 24);
-            $timeValue = implode(':', $arraySplit);
+        if (Preg::isMatch(self::EXTRACT_TIME, $timeValue, $matches)) {
+            if (empty($matches[6])) { // am/pm
+                $hour = (int) $matches[1];
+                $timeValue = ($hour % 24) . $matches[2];
+            } elseif ($matches[6] === $matches[7]) { // Excel wants space before am/pm
+                return ExcelError::VALUE();
+            } else {
+                $timeValue = $matches[0] . 'm';
+            }
         }
 
         $PHPDateArray = Helpers::dateParse($timeValue);
diff --git a/src/PhpSpreadsheet/Calculation/TextData/Format.php b/src/PhpSpreadsheet/Calculation/TextData/Format.php
index 57d3316637..5352b6d02b 100644
--- a/src/PhpSpreadsheet/Calculation/TextData/Format.php
+++ b/src/PhpSpreadsheet/Calculation/TextData/Format.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\TextData;
 
+use Composer\Pcre\Preg;
 use DateTimeInterface;
 use PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
@@ -128,8 +129,11 @@ public static function TEXTFORMAT($value, $format)
         $value = Helpers::extractString($value);
         $format = Helpers::extractString($format);
 
-        if (!is_numeric($value) && Date::isDateTimeFormatCode($format)) {
-            $value = DateTimeExcel\DateValue::fromString($value) + DateTimeExcel\TimeValue::fromString($value);
+        if (!is_numeric($value) && Date::isDateTimeFormatCode($format) && !Preg::isMatch('/^\s*\d+(\s+\d+)+\s*$/', $value)) {
+            $value1 = DateTimeExcel\DateValue::fromString($value);
+            $value2 = DateTimeExcel\TimeValue::fromString($value);
+            /** @var float|int|string */
+            $value = (is_numeric($value1) && is_numeric($value2)) ? ($value1 + $value2) : (is_numeric($value1) ? $value1 : (is_numeric($value2) ? $value2 : $value));
         }
 
         return (string) NumberFormat::toFormattedString($value, $format);
diff --git a/tests/data/Calculation/TextData/TEXT.php b/tests/data/Calculation/TextData/TEXT.php
index 5bf87a87df..a72351f668 100644
--- a/tests/data/Calculation/TextData/TEXT.php
+++ b/tests/data/Calculation/TextData/TEXT.php
@@ -71,6 +71,56 @@
         '2014-02-15 16:17',
         'dd-mmm-yyyy HH:MM:SS AM/PM',
     ],
+    'datetime integer' => [
+        '1900-01-06 00:00',
+        6,
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime integer as string' => [
+        '1900-01-06 00:00',
+        '6',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime 2 integers without date delimiters' => [
+        '5 6',
+        '5 6',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime 2 integers separated by hyphen' => [
+        (new DateTimeImmutable())->format('Y') . '-05-13 00:00',
+        '5-13',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime string date only' => [
+        '1951-01-23 00:00',
+        'January 23, 1951',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime string time followed by date' => [
+        '1952-05-02 03:54',
+        '3:54 May 2, 1952',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime string date followed by time pm' => [
+        '1952-05-02 15:54',
+        'May 2, 1952 3:54 pm',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime string date followed by time p' => [
+        '1952-05-02 15:54',
+        'May 2, 1952 3:54 p',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime decimal string interpreted as time' => [
+        '1900-01-02 12:00',
+        '2.5',
+        'yyyy-mm-dd hh:mm',
+    ],
+    'datetime unparseable string' => [
+        'xyz',
+        'xyz',
+        'yyyy-mm-dd hh:mm',
+    ],
     [
         '1 3/4',
         1.75,