base 25 is a positional numeral system with twenty-five as its base. It uses 25 different digits for representing numbers. The digits for base 25 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, n, and o.

base 27 is a positional numeral system with twenty-seven as its base. It uses 27 different digits for representing numbers. The digits for base 27 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, n, o, p, and q.