No, 16k accounts follow his. Of that, maybe a few hundred actually have users behind them that look at his tweets with any kind of frequency.
You can buy that kind of following for the price of a bottle of wine.
Not at all. I had more than that before I quit twitter and I am about as minor a figure in a sub-sub-sub-industry as one can be; actually-famous people have millions. Not-quite-famous people have hundreds of thousands.
16 thousand people follow him. That's way more than enough to be considered a 'public person'