Why is everything in computer science a power of $2$? [duplicate]

I have noticed this strange thing.All things related to Computers come in values which are powers of $2$.For eg. Rams come in $2,4,8$ or $16$ GB,pendrives and memory cards also come in similar values.Computers are $8,16$ or $32$ or $64$ bit values.

Everything remarkably a power of $2$.Why is everything $2^n$?

Why?Thanks for any help!!