Revealing mistake: When Fry starts his speech with "I, Fry", the podium is casting a shadow underneath him, but he isn't. (00:13:50)
Revealing mistake: When someone suggests crying as a way to get the emperor out of Fry's body, he says 'that's a great idea', the emperor's face stays still on Fry's stomach, instead of moving in sync with Fry's body. (00:15:50)
Answer: The initial number is 0101100101 = 357. When reflected in a mirror, however, it reads 1010011010 = 666 (the number of the Beast). It is a parody of The Shining, where the words Red Rum are seen as the word murder in the mirror.
Sierra1 ★