The duodecimal system (also known as base 12 or dozenal) is a positional notation numeral system using twelve as its base.
base 19
base 19 is a positional numeral system with nineteen as its base. It uses 19 different digits for representing numbers. The digits for base 19 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f, g, h, and i.