Its interesting to note that the Hebrew University of Jerusalem and Princeton University Press own the rights to all of Einstein's writings that were not copyrighted by anyone else.
They also authorised a Beverly Hills based licensing agency specialising in protecting and promoting the personas of world-renowned entertainment and historical personalities, to license Einstein's image for promotional purposes and to prevent unauthorized use of the likeness and image of him.
I wouldn't mind betting that the rights of E=mc^2 are also owned by them, also (??)
(I may stand corrected on this bit though …)
Cheers
PS:
Here ya go ...