The integer and double types are fine for most of the mathematical tasks that arise in Web scripting, but each instance of these types is stored in a fixed amount of computer memory, and so the size and precision of the numbers these types can represent is inherently limited. Although the exact range of these types may depend on the architecture of your server machine, integers typically range from
–2 to the power
31 – 1 to
2 to the power
31 – 1, and doubles can represent about 13 to 14 decimal digits of precision. For tasks that require greater range or precision, PHP offers the arbitrary-precision math functions (also known as BC functions, from the name of the Unix-based, arbitrary-precision calculating utility).
I can read about this somewhere else if I ever need to.