How is 999999 written in roman numerals?

Answer 1

The way we write out Roman numerals today differs in the way that the ancient Romans actually did themselves and they would have probably wrote out the equivalent of 999,999 simply as I(M) which means 1,000,000-1

Answer 2

999999 is written as CMXCIX in Roman numerals. C represents 100, M represents 1000, X represents 10, and IX represents 9. By combining these symbols, you get CMXCIX, which represents 900 + 90 + 9, or 999.