For me, the letters have the following colors:

ABCDEFGHIJKLMNOPQRSTUVWXYZ
Most of these were drilled into my head by a multicolored letter magnet set I used to play with when I was little, but some of the colors have changed from what they were in the magnet set. When I read a word, the word usually seems to be the color of the first letter of that word.

The numbers look like this:
123456789, plus the number 0 is white.