Another strange detail in The Shining is how much the number 42 appears in the film. Danny wears a shirt with the number on it, Dick’s rental car has the number on its license plate, and a news anchor mentions a “$42 million spending bill.” Also, when multiplied, the digits on Room 237 equal 42, and the number 21, which is half of 42, appears in the final photo saying 1921.
This just might be Kubrick subtly frightening the audience with a recurring symbol. However, I’m being completely serious when I say that some people theorize that this number is meant to reference the Holocaust, since Hitler’s Final Solution took place in 1942. I know that all sounds like a conspiracy theorist’s wet dream, but bear in mind, Jack actually uses an Adler typewriter used by the Nazis.
Source: https://www.buzzfeed.com/anthonyorlando52/details-in-horror-movies-that-chilled-me-to-the-bone