I dont know which one you're looking at but i dont come up with anywhere close to those rpms Here is the rundown on the motor on offshoreelectircs.com :

Product ID: fei-580-L
Feigao 580L "Long" Sized Brushless Motor Details


Feigao 580L "Long" motor for use with 30" - 40" mono or hydro boats. This motor will produce up to 1800 watts with the proper cooling.

If your a sport boater or top notch racer on a budget, the Feigao Line of motors is the Brushless motor for you! Feigao high performance brushless motors have the rpm and motor efficiency similar to motors like Hacker that are 2 to 4 times higher in Price!

feigao 580L: 580 6L 2,154 RPM / Volt (5)
580 7L 1,894 RPM / Volt (6)
580 8L 1,649 RPM / Volt (12)
580 9L 1,426 RPM / Volt (0)
580 10L 1,326 RPM / Volt (5)
580 12L 1,051 RPM / Volt (4)

the 8L will give you around 38,000 unloaded, that is more in the reasonable range, the 9L about 33,000.................