It’s amazing to me that this helicopter can generate enough lift to fly on Mars being that the Martian atmosphere is 1/100 the density of Earth. The blades must spin very fast.
As I recall, about 2,800 rpm.
Not so fast for a copter that size. It's comparable to RC helicopters here on earth.
The difference is that Ingenuity's blades are much wider in chord and have a lot of twist from hub to tip. They're more akin to propeller blades than helicopter blades.