The vigesimal or base 20 numeral system is based on twenty (in the same way in which the decimal numeral system is based on ten).
base 24
base 24 is a positional numeral system with twenty-four as its base. It uses 24 different digits for representing numbers. The digits for base 24 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f, g, h, i, j, k, l, m, and n.