Songfacts®:

• "Pennsylvania 6-5000" is the phone number of the Pennsylvania Hotel in New York City. Before area codes, the first two numbers were called the "Exchange Code," and were represented by a word whose first two letters were used as the numbers. Thus, "Pennsylvania" represented the PE exchange code, which translates to the number 73 (P=7, E=3). The number today, complete with area code, is (212) 736-5000.
• Bill Finegan and Jerry Gray wrote the music for this song, with Carl Sigman adding the lyrics. In The Carl Sigman Songbook, Sigman's son Michael writes: "in 1940, Carl came up with 'Pennsylvania 6-5000,' cashing in on the popularity of Café Rouge, a hot nightclub situated in New York City's Hotel Pennsylvania, frequented by Swing Era icons like Goodman, the Dorsey Brothers, Artie Shaw, and Glenn Miller. (Its phone number was, yes, you guessed it.) The Glenn Miller recording—which repeats 'Pennsylvania 6-5-0-0-0' over and over, sometimes at the expense of the clever verses—became a smash hit, reaching the top five on the pop charts. The song was also covered by the red-hot Andrews Sisters, who sang all the verses that other artists omitted. Sixty-five years later, 'Pennsylvania 6-5000' is still a worldwide standard covered by artists from Brian Setzer to Heptet and used in movies from The Glenn Miller Story to Oliver Stone's football flick Any Given Sunday. If you call Pennsylvania 6-5000 today, you'll still get the main switchboard of that legendary hotel across the street from Pennsylvania Station."