Every propeller or wind turbine has only 3 blades,reason is wake behind each blade interfer with next blade.

I think airflow (head wind caused by aircraft speed) that comes to propeller must clear this wake,so faster you go the air for each blade has better quality.

How then wake interfer with blade?

(Same like in Formula 1, there is no wake for car that drives behind car if cross wind is blowing.
Or there is not turbulence at airfield when plane take off if cross wind is blowing)