 <p>First, </p> <blockquote> <p>int and long were "unified" a few versions back. Before that it was possible to overflow an int through math ops.</p> <p>3.x has further advanced this by eliminating int altogether and only having long.</p> </blockquote> <p>Based on question here, <a href="http://stackoverflow.com/questions/2104884/how-does-python-manage-int-and-long">How does Python manage int and long?</a></p> <p>Also, there is no longer a limit on <code>integers</code> according to <a href="http://docs.python.org/3.1/whatsnew/3.0.html" rel="nofollow">http://docs.python.org/3.1/whatsnew/3.0.html</a></p> <blockquote> <p>The sys.maxint constant was removed, since there is no longer a limit to the value of integers. However, sys.maxsize can be used as an integer larger than any practical list or string index. It conforms to the implementation’s “natural” integer size and is typically the same as sys.maxint in previous releases on the same platform (assuming the same build options).</p> </blockquote> <p><strong>Basically</strong>:</p> <p><em>Python seamlessly converts a number that becomes too large for an integer to a long.</em></p> <p>Docs <a href="http://docs.python.org/release/1.4/ref/ref5.html" rel="nofollow">here</a></p>