diff --git a/Lib/imputil.py b/Lib/imputil.py
index 6d99ec1..a0099a8 100644
--- a/Lib/imputil.py
+++ b/Lib/imputil.py
@@ -476,7 +476,7 @@
         s = _os_stat(pathname)
     except OSError:
         return None
-    return (s.st_mode & 0170000) == 0040000
+    return (s.st_mode & 0o170000) == 0o040000
 
 def _timestamp(pathname):
     "Return the file modification time as a Long."