The whole context of Revelation pretty well confirms it. I understand why people will be hesitant to speculate based on various theories about Revelation though.Nope, but it's also wise to understand that, since God in His entirety is well outside our ability to comprehend, there will be "Mysteries".
SO how do you propose to define authoritatively which "number" is right???? "Experts" will swear to one or the other, and all you really have is "human opinion", and human "theology".