After the episode ‘47 Seconds’, the fandom started to notice things with the number relevant to the show. Like in the Blue Butterfly ep, it took place in 1947, the kiss in ‘Always’ lasted for 47 seconds, Caskett’s first kiss was in the 47th episode (in Knockdown) and I’m not sure (correct me if I’m wrong since this is all by recalling things I read on my dash) that the motel room in 3XK was Room 47.
I don’t know if the numerology is intended by the writers, but I find it really amazing.
Update: Kate has four letters, Beckett has seven letters. (sent by anon)