Channing Tatum revealed in an interview with Ellen DeGeneres that he wore an oversized prosthetic ACE bandage sleeve for the scene where he walks naked in front of Rachel McAdams character in order to get a realistic reaction out of her. This was apparently the take that was used in the final cut. It is confirmed by the director that it was the first take.
The café that Leo and Paige frequent is called Cafe Mnemonic. A mnemonic device is a learning technique used to help memory.
Loosely based on the story of Kim and Krickitt Carpenter. The Carpenters liked the movie but were disappointed by its omission of their faith in Christianity which was an important factor in their resilience. They considered some of the scenes hard to watch.
In October of 2018 the couple who inspired the story, Kim and Krickitt Carpenter, announced that they were divorcing after 25 years of marriage. The reason given was that Krickitt had discovered that Kim had an affair and he'd admitted to it.