By my count, the number of people is probably more like less than 1000. And that's only because they are forced, generally as a requirement of employment, to be there.
I do expect somewhere between 499,000 and 699,000 drones and zombies and various forms of sycophants to attend as well, though.
Just checked the ucam or whatever it is. Appears to be trillions of fans there. NOT! We had a better turn out at the Gun Appreciation rally in Carson City this past weekend. And unlike these clowns in dc, they all love the constitution and bill of rights. No mess to clean up either. At least the trash will be less for the union sanitation workers to clean up after the slobs leave the mall. And the crowds too.