How many pins of the Arduino Micro are really useable as digital I/O pins?

@Mike1,
What I mean is that if you know about SPI then you know those labels are irrelevant unless you included the SPI library in the sketch. Otherwise, they are just digital pins like any others. The flip side of that coin is you can't use them for anything else when
you're running a SPI app. Pin 10 is sometime s an SD chip select and it has to be reassigned if your using SPI.