You can use xlrd
s helper function:
import xlrd
print xlrd.colname(56)
# BE
Strangely - there doesn't appear to be a direct equivalent in xlwt
or xlwt.Utils
(although this does have various helper functions for conversion of cells and names)
Going by the question's title - you can use:
>>> xlwt.Utils.rowcol_to_cell(5, 2)
'C6'