using double @s simply employs the algebra filter as opposed to the tex filter, and frankly I do not know why anyone would want to use both, as the algebra filter is a subset of the tex filter and having both filters running means the file has to be parsed twice.....
In tex, curly braces can be used to group arguments, so for a doubel digit exponent you can do 2^{33}, which will appear as:
$$2^{33}$$