welcome to CPF!!
you'll find that flashlights come in MANY variations of cell count...
from 1-8 cells is very common.... and they aren't always common alkaline AA, C, and D cells.. some high power flashlights use lithium, lithium-ion, NIMH, NICD, and lead acid batteries.... many of which provide better power density than alkalines, and some are rechargable...
maglight makes 1 cell, 2, 3, 4, 5, and 6 cell flashlights...