This is quite important. I've tripped breakers pulling too many amps to the point power cord prongs would burn the skin and the breaker panel was hot to the touch--I never want to get in that situation again.No, it's not called adapters. Wiring up some kind of adapter to allow that UPS to utilize a standard household power outlet could be trouble.
There's a real, non-arbitrary reason the engineers specified that particular plug not the normal one when they designed that UPS. They built the unit to pull more current than can safely be provided by the 15 A power outlets used in most homes. Trying to use it in such a manner could, at the least, cause a number of circuit breaker trips, and would easily be a fire hazard.
You can check your breaker to see if it's 20a to begin with, and if there's nothing else on that circuit (I mean NOTHING), you can probably adapt it and use it. But you need to be very careful with things like this and check regularly for oddities like warm power cords, etc.