Twitter numbers ,and social media numbers in general, are such a waste to track. I honestly would bet my limbs that Katy Perry isn't followed by 70 million real people. The same goes for many other celebs.
Though about half of my followers are just from ATRL Then the other half are mostly just inactive or simply random people. I don't tweet much anyways so I don't really care about my follower count anymore, though it's just interesting to see who unfollows because if I was following them, I'll clock thaT right back.