Il numero romano MMMCDXCI nel sistema decimale vale: 3491.
MMMCDXCI in latino si scrive tria milia quadringenti nonaginta unus,
mentre in italiano tremilaquattrocentonovantuno.
MMMCDLXXII, MMMCDLXXIII, MMMCDLXXIV, MMMCDLXXV, MMMCDLXXVI, MMMCDLXXVII, MMMCDLXXVIII, MMMCDLXXIX, MMMCDLXXX, MMMCDLXXXI, MMMCDLXXXII, MMMCDLXXXIII, MMMCDLXXXIV, MMMCDLXXXV, MMMCDLXXXVI, MMMCDLXXXVII, MMMCDLXXXVIII, MMMCDLXXXIX, MMMCDXC, MMMCDXCII, MMMCDXCIII, MMMCDXCIV, MMMCDXCV, MMMCDXCVI, MMMCDXCVII, MMMCDXCVIII, MMMCDXCIX, MMMD, MMMDI, MMMDII, MMMDIII, MMMDIV, MMMDV, MMMDVI, MMMDVII, MMMDVIII, MMMDIX, MMMDX