What is the number RSA 2048 used for?
Is this number used for factoring challenge only? Lets say one day a VERY VERY lucky guy just GUESS the factor P and Q correctly will there be any security issue in the world. Is anyone using this particular RSA 2048 for anything?


I don't believe so.  On occasion, the need for a composite of unknown (to anybody) factorization comes up; someone might be using it for that.  Such numbers are harder to generate than you might think;  if you just select a random 2048 value, find that it is composite, and run ECM on it a bunch, well, you won't know whether running ECM a bit longer would find the factorization.  Using one of the RSA challenge numbers would make sense in that case, but again, I don't know of anyone who's actually doing it.

On the other hand,


  Cracking this one by luck doesnt mean much right?


While there isn't a great deal of significance to this specific number, if someone did manage to factor it, it would certain raise the issue whether other 2048 bit numbers were hard to factor (which, incidentally, is precisely why RSA generated their challenge numbers in the first place)