Yes.
Yes.
64
64 and 121 share the common factor of 1.
They are not a direct bolt on but they can be made to fit.
I am still looking
The average iTunes song is around 8 megabytes, so about 8,192 songs can fit on 64 gigabytes.
9, remainder 1
64
very possible.
There is no number that can fit evenly into both numbers.
Exactly 32 times