Greatest mathematician ever?
As brilliant as this dude was, and of course not counting Newton (the obvious choice for #1) considering him as a physicist, to me, the greatest of them all is Euler.
Then Gauss, then Laplace, then the rest.
Tough one. Not counting Newton, I am inclined to agree with Euler but would give a shout-out to Euclid for kinda kicking things off in a way. And Cauchy for just the sheer number of things named after him!
"We're fighting an army of robots... and I have a bow and arrow."