None. That is not a Roman numeral.
In Roman numerals it is the year MCMLXIV. In Arabic numerals it is the year 1964.
MCMXXI represents the year 1921 in Roman numerals.
It is not equivalent to any year because they are an invalid arrangement of Roman numerals
The year 1958 is written as MCMLVIII in Roman numerals.
In todays modern notation of Roman numerals it is: MCMLVI
In Roman numerals it is the year MCMLXIV. In Arabic numerals it is the year 1964.
The year 1450 is written in roman numerals as MCDL.
MCMXXI represents the year 1921 in Roman numerals.
It is not equivalent to any year because they are an invalid arrangement of Roman numerals
The year 1958 is written as MCMLVIII in Roman numerals.
In todays modern notation of Roman numerals it is: MCMLVI
In todays notation of Roman numerals: MCMLXXXV
The number (or year) 2009 in Roman numerals is MMIX
MMX is Roman Numerals for the year 2010.
MDCCCLXXI in Roman numerals represents the year 1871.
We started Roman Numerals in about the year of 1389 AD I think.
In today's modern notation of Roman numerals: 1985 = MCMLXXXV