Here's how to calculate that:

* Mach 1 is the speed of sound, which is approximately 767 mph at sea level.

* Mach 23 is 23 times the speed of sound.

* Mach 23 x speed of sound = 23 x 767 mph = 17,641 mph

Keep in mind that the speed of sound can vary depending on factors like altitude and temperature. This calculation uses the approximate speed of sound at sea level.