Hidden Power is based on the Pokemon's IVs. IVs are basically a hidden value that help determine part of a Pokemon stats. There is no way for you to see the actual values, but there are ways for you to find them. However, these ways might involve you having a grasp of EVs and (Ev training) and making use of an IV calculator.
The IVs are placed in some Hidden Power formula that determines both Hidden Power's battle power (ranges from 30-70) and typing (all but Normal are possible).
Pretty much any Pokemon with a decent Special Attack stat could benefit from having Hidden Power due to it being flexible. However, Hidden Power can easily be outclassed by better attacks. In short, if the Special Attack stat is decent, and if the Pokemon doesn't have any better moves to use, it COULD benefit from Hidden Power... and it doesn't mean it will since there is no way for you to control if you're going to end up with a strong 70BP Hidden Power or a weak 30BP Hidden Power (at least on one specific Pokemon - you can always capture/breed more until you get the Type/Power combination you want).
HOPE I HELPED ^_^