diff --git a/telethon/errors/__init__.py b/telethon/errors/__init__.py
index 38696ada..0d101eeb 100644
--- a/telethon/errors/__init__.py
+++ b/telethon/errors/__init__.py
@@ -69,4 +69,4 @@ def rpc_message_to_error(rpc_error, report_method=None):
     if cls:
         return cls(rpc_error.error_message)
 
-    return RPCError(rpc_error.error_code, rpc_error.error_message)
+    return RPCError(rpc_error.error_message, rpc_error.error_code)
diff --git a/telethon/errors/rpcbaseerrors.py b/telethon/errors/rpcbaseerrors.py
index 78547017..2ff3b47f 100644
--- a/telethon/errors/rpcbaseerrors.py
+++ b/telethon/errors/rpcbaseerrors.py
@@ -3,8 +3,8 @@ class RPCError(Exception):
     code = None
     message = None
 
-    def __init__(self, code, message):
-        super().__init__('RPCError {}: {}'.format(code, message))
+    def __init__(self, message, code=None):
+        super().__init__('RPCError {}: {}'.format(code or self.code, message))
         self.code = code
         self.message = message