The word "forever" is said in every episode.
As of April 2018, there remains an active effort by fans of the show to have it brought back into production.
The only concentration camp to tattoo numbers on prisoners was at Auschwitz and rarely on babies. When babies were tattooed with numbers it was generally on their thigh or bottom as their arms were too small.
Judd Hirsch plays Abe, and his younger self (seen in flashbacks) is played by David Krumholtz. Krumholtz played Hirsch's son in Numb3rs (2005).
200-year-old Henry 'Hank' Morgan shares his name with the main character of Mark Twain's "A Connecticut Yankee in King Arthur's Court". Henry Morgan is also the name of the 17th-century privateer as depicted on the "Captain Morgan" rum label.