I used to work for an egg wholesaler. We paid the farmers by the egg according to grade. We accounted in eggs.<p>Do you know how many eggs are sold in the UK?<p>We had to write a special class to handle eggs because we blew the unsigned integer on a VAX.
You don't have much space left in 64 bits for some financial numbers. FX swap trades with a billion dollars on one side and some very devalued currency on the other (e.g. zimbabwe dollars 1:60,000,000 at one point).<p>It gets worse when you start adding those numbers up.
Heh, I actually overran a signed integer 2 years ago in an app for a major financial company.<p>Yes, that's > $2,147,483,647<p>Thanks, subprime mortgage crisis!
Huge. Longer than 2^30 digits. I was working on statistics. Doing probabilities requires doing some crazy factorials. These often require handling large freaking numbers. I'm a PHP guy, so BC Math and GMP Math are my saviors in this area.<p>Thankfully, all the huge numbers are just in the computation of the statistics and don't need to be stored long term in a database. The thought of having to store an integer in a BLOB is frightening.
If you want universal uniqueness you should be looking at 128-bits (<a href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier" rel="nofollow">http://en.wikipedia.org/wiki/Universally_Unique_Identifier</a>)
I built an aviation mapping engine that used fixed point math for lat/lon representation. It basically used an entire 32bit signed int and gave a guaranteed minimal resolution of 3 feet. It would quite often go to the ragged edge of what you can fit in a 32 bit quantity.<p>The fun bit was that you had to use 2 combined registers (ARM) to represent a 64bit quantity so you could do multiplication and keep all your precision.<p>Oh, for the luxury of a FPU...
factorial(30..50) -- for factoradics (<a href="http://en.wikipedia.org/wiki/Factoradic" rel="nofollow">http://en.wikipedia.org/wiki/Factoradic</a>). Representing the reproducable state of a list of randomly ordered items.
I implemented Tupper's Self-referential formula which depends on an extremely large number (although I suppose that's cheating a bit, the number is actually an encoding of a bitmap).
I've had to build a system to theoretically handle indexes up to 1.2553643905927429e+30 but we haven't got that far yet (biggest # is a billion billion billion or so)