diff --git a/apns.py b/apns.py
index ec52fd2..0310267 100644
--- a/apns.py
+++ b/apns.py
@@ -81,7 +81,7 @@
      'I'   # identifier
     )
 
-TOKEN_LENGTH = 32
+TOKEN_LENGTH = int(32)
 ERROR_RESPONSE_LENGTH = 6
 DELAY_RESEND_SEC = 0.0
 SENT_BUFFER_QTY = 100000
@@ -135,7 +135,7 @@ def packed_uint_big_endian(num):
         """
         Returns an unsigned int in packed big-endian (network) form
         """
-        return pack('>I', num)
+        return pack('>I', int(num))
 
     @staticmethod
     def unpacked_uint_big_endian(bytes):
@@ -513,7 +513,7 @@ def _get_enhanced_notification(self, token_hex, payload, identifier, expiry):
         token = a2b_hex(token_hex)
         payload = payload.json()
         fmt = ENHANCED_NOTIFICATION_FORMAT % len(payload)
-        notification = pack(fmt, ENHANCED_NOTIFICATION_COMMAND, identifier, expiry,
+        notification = pack(fmt, ENHANCED_NOTIFICATION_COMMAND, identifier, int(expiry),
                             TOKEN_LENGTH, token, len(payload), payload)
         return notification