Close, but it actually turns the prop slower. The outrunners run slow and strong and do not need the gearbox. Where inrunners or standard electric motors turn much higher rpm per volt (KV) at lesser torque.
The AXI for instance is a 1080kv so 1080 rpm per volt. Where say the Himax 2015-4200 is a 4200kv so gearing it down 4:1 would give roughly the same rpm at the prop. There are, of course, other factors but that's a start.

Derek