Actress Shohreh Aghdashloo played God in the original cut of the film. According to Shohreh Aghdashloo herself in a Los Angeles Times interview, she was replaced by the studio because she was born a Muslim and the studio wasn't ready for Muslim to portray God in a movie. Her exact quote: "Oh, my God, I loved that role. As actors, we all know we're at the mercy of the editing table, but not to this extent, never had I experienced it. The director, George Nolfi, decided I should play God. Everything went great until I got a call from the director who was asking to have lunch with me. He was on the verge of crying. He said, the distribution company believes that you cannot play this role....That's right, although if I'm asked what religion I am, I say I was born a Muslim. I don't introduce myself as a Muslim woman, but I guess the distribution company put the dots together and felt it's too early for this."
The phone number given to Matt Damon by Emily Blunt in the movie ((212) 664-7665) is owned by Universal Studios and has appeared in other films distributed by the company (Definitely, Maybe (2008), Scott Pilgrim vs. the World (2010)) in an effort to avoid the much overused "555" prefix. If called, it will ring indefinitely.
The visual effect on Top of the Rock, where they run up the stairs to the observation platform, turn around and go down the stairs, and find themselves still on the observation platform, was nicknamed the "M.C. Escher stairs" shot.
Early in the film, when David delivers an address at Fordham University, he is standing on the "Terrace of the Presidents", which is inscribed with the names of heads of state who have received degrees or honorary degrees from the university.
One of the production companies for this film is Electric Shepherd Productions, so named for the novel "Do Androids Dream of Electric Sheep" (source of Blade Runner (1982)) by Philip K. Dick, who also wrote the short story, "The Adjustment Team" on which this film is based.