I have had one survive several hours lying on the gravel after a tank leaked dry but there is no recorded time of survival out of water as far as I know.
Betta fish do very well in aquariums as they get along surprisingly well with other fish of their average size size. Betta fish will live longer when they live in a filtered aquarium above 3 gallons....
If you put more than one male together, they will fight to the death. Females are less "pretty" than the males, and are fine in a tank with other females.