It all depends what you mean by real and you get into one of those arguments about the meanings of words which wastes everyone's time.

Numbers certainly seem to be more real than most other things, if indestructibility is anything to go by. You could remove all the matter and energy in the universe and pi would still be 3.14 and a bit.

The old programmer's joke about 'God is real, unless declared integer' seems to be heading towards this thread with an awful inevitability.