Is it true that Bitcoin (1400B$ cap) is standing on a 17.5 billion $ worth of mining equipment

I recently read more about the possibilites of 51% attacks. Good to know, while being an issue they arent a nuclear bomb after all. They could cause harm but not in a way some people would like to FUD about.

Anyways, I was interested to know how much such an attack would cost, for example for a government or a rich individual.

I took one of the Bitman stats which are: 234TH/s 3510W for 6300$ per unit.

The current Bitcoin hashrate stands at 650.000.000TH/s, so we need at least that.

650.000.000/234=Would be 2777777 mining devices. In a world without supply and demand that would be: 17.499.995.100$ or 17.5B$

In electricity it would demand 2777777*3510W = 9749MW. That would be 8 to 9 nuclear reactors.

Are those calculations correctly?