How long does it take to fly from Denver to Dubai?

A random search for flights from Denver (DEN) to Dubai (DXB) shows:

OPTION 1: 20hr 15min via Houston Intercontinental (IAH)

DEN - IAH United Airlines Flt 490 Dep 12:30pm 29Jul,Thu

IAH - DXB Emirates Airlines Flt 212 Dep 06:50pm 29Jul,Thu

Flight Duration: 17hr 21min; Layover Time: 2hr 54min; Total Trip Time: 20hr 15min