They are meaningless because they are an invalid arrangement of Roman numerals
You have already given it in Roman numerals
In Roman numerals, MMMD is MMMD. In Hindu-Arabic numerals, it is 3500.
Under today's rules the Roman numerals CMXLVII represent 947.
It is nothing. That is not a roman numeral!
399
190
1,915
1955
365
1910
48
1907