You should do a cluster on that beast. Airstart a few longer burn O motors.
Tried to bargain with these guys, told 'em "Well then, I'll just buy it from one of those vendors in China. They all advertise free shipping. So THERE!" Didn't work, they were firm on the price.If you're shopping, here's the Orbital ATK catalog:
http://www.orbitalatk.com/flight-systems/propulsion-systems/docs/2016 OA Motor Catalog.pdf
A waste of a perfectly good motor.
And at 2,247,233 lbf average thrust, I think that works out to AD9996190.
To answer the original question, the strongest motor (total impulse) you can buy is the SLS Booster. (298,000,000 lbf-sec / 1,325,570,041.35 N-s)