Why an odd number of blades in the cooler?

Question

Iron

Why does the fan have an odd number of blades Google didn’t say anything intelligible, can anyone explain in an accessible language ...

Answer 1

It's a manufacturer's conspiracy. If there were an even number of blades, then having broken one, it would be enough to break off the opposite one, and the cooler works again. So just throw it away and buy a new one.
Not really. This is done to reduce noise. On fans, they usually make not just an odd, but a simple number of blades: 3, 5, 7, 11 ... This aerodynamics cannot simply be explained on the fingers, but the fewer possible resonances the system has, the quieter it is.

Answer 2

Because if there was an even number, then it would be a plane and not a cooler!