Il numero romano MMMCDXXIII nel sistema decimale vale: 3423.
MMMCDXXIII in latino si scrive tria milia quadringenti viginti tres,
mentre in italiano tremilaquattrocentoventitré.
MMMCDIV, MMMCDV, MMMCDVI, MMMCDVII, MMMCDVIII, MMMCDIX, MMMCDX, MMMCDXI, MMMCDXII, MMMCDXIII, MMMCDXIV, MMMCDXV, MMMCDXVI, MMMCDXVII, MMMCDXVIII, MMMCDXIX, MMMCDXX, MMMCDXXI, MMMCDXXII, MMMCDXXIV, MMMCDXXV, MMMCDXXVI, MMMCDXXVII, MMMCDXXVIII, MMMCDXXIX, MMMCDXXX, MMMCDXXXI, MMMCDXXXII, MMMCDXXXIII, MMMCDXXXIV, MMMCDXXXV, MMMCDXXXVI, MMMCDXXXVII, MMMCDXXXVIII, MMMCDXXXIX, MMMCDXL, MMMCDXLI, MMMCDXLII