As many as there can be, As long as they keep tieing they can be as many as possible.
If a game is that miraculous then Yes it can go 5 overtimes
as many as needed, games are usually decided in 1 or 2, but there is no limit
As far as college and NBA is concerned, there is no limit as to the number of overtimes that can be played before determining a winner of the game.
Bulls vs Celtics with 6 overtimes Indianapolis Olympians vs Rochester Royals with 6 overtimes
As far as international, NBA, and US college basketball is concerned, there is no limit as to the number of overtimes that can be played.
Usually an overtime lasts 5 minutes but it depends how many overtimes they go in to.
6 Rochester Royals Vs. Indianapolis Olympians