ArangoDB 2.8 now provides a dedicated AQL function for exponentiation. This will save users a lot of trouble in case exponentiation is needed inside an AQL query, which up to 2.7 required writing and registering an AQL user-defined function.
With 2.8 it becomes as simple as
RETURN POW(2, 16) to raise 2
to the power of 16 from inside AQL.