Total number of possible color combinations

I calculated there to be 16,777,216 possible hex color code combinations.

The maximum possible characters that we can have in a single hexadecimal character is 16 and the maximum possible characters a hex color code can contain is 6, and this brought me to my conclusion of 16^6.

Is this correct? If not, please tell me how many possible color combinations there are and how it can be worked out.