Base 4. Higher bases (base 5, base 6, etc.) also contain those digits, as well as others.
123
one hundred twenty three (123).
123 = CXXIII
123
in numerals, 123 bundles of 10 straw
123
CXXIII
It is already in Hindu-Arabic numerals but if you mean in Roman numerals then it is written as: CXXIII
3 digits
BBB, which is 123-1 = 1728-1 = 1727 in base 10.
Iiiiiii,vvviImproved answer:In today's terms 123,456 in Roman numerals is (CXXIII)CDLVI
This cannot be determined because the number 3 does not exist in base 3; only 1 and 2 do.