1 (Simple) Line of Code Exploding my Brain

die(100000002568456);

Results in the following being printed:
100000002568460

Is this a bug in PHP…? I have no idea why this would happen except for possibly something to do with 64 bit numbers. How do I get it to work correctly?

PHP version is 5.2.6, I know it’s a few months out of date but it would really be a pain to upgrade PHP on these servers if I don’t have to.