Il numero romano CDXXXI nel sistema decimale vale: 431.
CDXXXI in latino si scrive quadringenti triginta unus,
mentre in italiano quattrocentotrentuno.
CDXII, CDXIII, CDXIV, CDXV, CDXVI, CDXVII, CDXVIII, CDXIX, CDXX, CDXXI, CDXXII, CDXXIII, CDXXIV, CDXXV, CDXXVI, CDXXVII, CDXXVIII, CDXXIX, CDXXX, CDXXXII, CDXXXIII, CDXXXIV, CDXXXV, CDXXXVI, CDXXXVII, CDXXXVIII, CDXXXIX, CDXL, CDXLI, CDXLII, CDXLIII, CDXLIV, CDXLV, CDXLVI, CDXLVII, CDXLVIII, CDXLIX, CDL