Help: writing stored procedure

I need to write a stored procedure that will convert a long value into a 3 character base 36 string. The 36 digits are 0123456789ABCD...Z. An example would be that the number 13330 would be converted to "AAA". This can be shown: (10 X 36squared) + (10 X 36) + (10 X 1) = 13330 'A' 'A' 'A' = "AAA" Thanks, Mike