>>42509480
Equestria has Manehattan and other metropolises, so at least low millions, but most of the population is there. Most of the population is in those cities, though. Ponyville has less than a thousand ponies. Other farming villages barely affect the total count, despite providing all of the food needed to support them.
Anywhere else on the planet not tamed by Equestria is nearly uninhabitable, and so, uninhabited.