diff --git a/Lib/encodings/__init__.py b/Lib/encodings/__init__.py
index 025b7a8..c3fe93d 100644
--- a/Lib/encodings/__init__.py
+++ b/Lib/encodings/__init__.py
@@ -85,5 +85,9 @@ def search_function(encoding):
     norm_encoding = normalize_encoding(encoding)
     aliased_encoding = _aliases.get(norm_encoding) or \
                        _aliases.get(norm_encoding.replace('.', '_'))
+
+    if aliased_encoding is None and norm_encoding.isdigit():
+        return search_function("cp" + norm_encoding)
+
     if aliased_encoding is not None:
         modnames = [aliased_encoding,
                     norm_encoding]