Honestly, I find that a lot of mathematical constants are pre-programmed in to most calculators, especially the ones which are complex enough for you to program in your own functions. I have a little Casio non-graphing calculator, but it still has something like 40 constants programmed in (with a legend showing which key combo is for which constant on the cover). Check your manual, or see if there's a "Constants" function, and you might find all that you need, and more.

If not, I'll pull mine out and give you all that it contains.