User blog comment:TheMostAwesomer/Some things/@comment-180.214.232.83-20141220181138/@comment-1605058-20141220182408

Definitions of abstract from The Free Dictionary: "Considered apart from concrete existence". In most philosophies, numbers aren't physical objects, they are just concepts, or objects which live in their own world, a world of ideas, and not a world of physical reality. I think this is enough to classify concept of "number" as abstract.

About exponentiation, it's even worse, because, what physical interpretation of exponentiation in our three (four?) dimensional world?