No, they're all the same. Each string is tuned in the same manner. However, it may be found to be more difficult to play certain chords on an acoustic than an electric due to neck differences, but...
6 strings
There are six(6) strings just like any normal guitar of any type.
Most acoustics have 20 frets, while some have 19. Some acoustic-electrics will have 21.
six... usually you can get more for ex 12.