Well, the first question one should ask is, "Has your Perl been build with 64 bit integer support?".

If the answer is yes, you should have 64 bit precision on your integers. If the answer is no, you can expect about 56 bits of precision on your integers. You may wonder, "why not 32"? That is, if your integers would overflow, perl automatically start using a double instead. And that will give you about 56 bits of precision.

You can find out whether your Perl support 64 bit integers by doing a 'perl -V'. The 64bitness of the hardware is neither sufficient, nor a requirement.

Abigail