No. Even without hating on the prequels, it can be said they are not needed to watch The Force Awakens. You should however watch the original trilogy, as this is not a standalone movie.
Add:
HIGHLY RECOMMENDED that you watch the De-specialized editions of the OT you can find online. The original versions are no longer available commercially, and the ones that you can buy have so many changes that make the movies worse and borderline unwatchable.