Short answers, pulled from the story.
The world premiere took place at Loew's State Theatre on the 14th of March 1972. Production costs totaled only $6.5 million while profits caused Gulf & Western Industries stock to jump from 77 cents per share to $3.30 within a single year according to a Los Angeles Times article dated the 13th of December 1972.
Marlon Brando agreed to play Don Vito Corleone after performing a screen test at his California residence. He stuffed cotton balls into his cheeks and used shoe polish to darken his hair for the audition before accepting a lower salary and posting a bond to ensure he would not cause delays.
Approximately 90 percent of the movie was shot on location in New York City and its surrounding suburbs using over 120 distinct locations. Scenes set in Las Vegas were not filmed on location due to insufficient funds while the remaining portions were shot in California or Sicily where towns like Savoca and Forza d'Agrò provided romantic countryside backdrops for Michael's exile period.
When the Academy Awards committee reviewed Rota's nomination they discovered he had used similar material in another film. This led to the revocation of his Best Original Score award though he still won a Grammy Award later that year despite critics praising the album as dark looming and elegant.
Within eighteen weeks the film had grossed $101 million making it the fastest movie ever to reach that milestone. Total earnings eventually reached between $250 million and $291 million worldwide through multiple re-releases including a limited run in 1997.