Il numero romano MMMMCDXXIII nel sistema decimale vale: 4423.
MMMMCDXXIII in latino si scrive quattuor milia quadringenti viginti tres,
mentre in italiano quattromilaquattrocentoventitré.
MMMMCDIV, MMMMCDV, MMMMCDVI, MMMMCDVII, MMMMCDVIII, MMMMCDIX, MMMMCDX, MMMMCDXI, MMMMCDXII, MMMMCDXIII, MMMMCDXIV, MMMMCDXV, MMMMCDXVI, MMMMCDXVII, MMMMCDXVIII, MMMMCDXIX, MMMMCDXX, MMMMCDXXI, MMMMCDXXII, MMMMCDXXIV, MMMMCDXXV, MMMMCDXXVI, MMMMCDXXVII, MMMMCDXXVIII, MMMMCDXXIX, MMMMCDXXX, MMMMCDXXXI, MMMMCDXXXII, MMMMCDXXXIII, MMMMCDXXXIV, MMMMCDXXXV, MMMMCDXXXVI, MMMMCDXXXVII, MMMMCDXXXVIII, MMMMCDXXXIX, MMMMCDXL, MMMMCDXLI, MMMMCDXLII