To establish the number of available colours, raise the value 2 to the power of this value.
The technical description of this value is that it is the base-2 logarithm of the number of colours available.
You will likely get one of the following values:
1 bit - black and white
8 bits - 256 colours
16 bits - thousands of colours
24 bits - millions of colours
32 bits - millions of colours (possibly with transparency thrown in)
Other values are possible but unlikely.