diff --git a/JSONObject.java b/JSONObject.java
index de42faa..c722ea6 100644
--- a/JSONObject.java
+++ b/JSONObject.java
@@ -1733,9 +1733,12 @@ public class JSONObject {
             }
             if (object instanceof JSONObject || object instanceof JSONArray
                     || NULL.equals(object) || object instanceof JSONString
-                    || object instanceof Number || object instanceof Character
-                    || object instanceof Boolean || object instanceof String
-                    || object instanceof Enum) {
+                    || object instanceof Byte || object instanceof Character
+                    || object instanceof Short || object instanceof Integer
+                    || object instanceof Long || object instanceof Boolean
+                    || object instanceof Float || object instanceof Double
+                    || object instanceof String || object instanceof BigInteger
+                    || object instanceof BigDecimal || object instanceof Enum) {
                 return object;
             }