diff --git a/src/PhpSpreadsheet/Shared/Date.php b/src/PhpSpreadsheet/Shared/Date.php
index 91c3ee0e..11293136 100644
--- a/src/PhpSpreadsheet/Shared/Date.php
+++ b/src/PhpSpreadsheet/Shared/Date.php
@@ -325,11 +325,12 @@ class Date
      */
     public static function isDateTime(Cell $pCell)
     {
-        return self::isDateTimeFormat(
-            $pCell->getWorksheet()->getStyle(
-                $pCell->getCoordinate()
-            )->getNumberFormat()
-        );
+        return is_numeric($pCell->getValue()) &&
+            self::isDateTimeFormat(
+                $pCell->getWorksheet()->getStyle(
+                    $pCell->getCoordinate()
+                )->getNumberFormat()
+            );
     }
 
     /**