It is the 15th prime number and the 8th Lucas number.
There exists a humorous 47 society at Pomona College, California, USA which propagates the (joking) belief that the number forty-seven occurs in nature with noticeably higher frequency than other natural numbers.
Following on from this inside joke, Joe Menosky, who graduated from Pomona College in 1979 and went on to become one of the story writers of Star Trek: The Next Generation, "infected" other Star Trek writers with it, and as a result the number occurs in a subtle hidden way in almost every episode of this programme and its sequels Star Trek: Deep Space Nine and Star Trek: Voyager. According to a (joking) statement by Rick Berman (the co-creator and executive producer of several Star Trek series), "47 is 42, corrected for inflation.".
Forty-seven is also
The following were used as references: