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
To convert the base 10 number 123 to binary, we repeatedly divide the number by 2 and record the remainders. Starting with 123, the division yields remainders of 1, 1, 0, 1, 1, 1, and 0, which we read in reverse order. Thus, the binary representation of 123 is 1111011.
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