alphalph – Convert numbers to letters

Pro­vides com­mands \al­phalph and \AlphAlph. They are like \num­ber but the ex­pan­sion con­sists of low­er­case and up­per­case let­ters re­spec­tively (1 to a, 26 to z, 27 to aa, 52 to zz, 53 to ba, 702 to zz, 703 to aaa, etc.). Can be used as a re­place­ment for LaTeX's \@alph and \@Alph macros.
The pack­age is part of the oberdiek bun­dle.