Il numero romano MMMDCXCI nel sistema decimale vale: 3691.
MMMDCXCI in latino si scrive tria milia sescenti nonaginta unus,
mentre in italiano tremilaseicentonovantuno.
MMMDCLXXII, MMMDCLXXIII, MMMDCLXXIV, MMMDCLXXV, MMMDCLXXVI, MMMDCLXXVII, MMMDCLXXVIII, MMMDCLXXIX, MMMDCLXXX, MMMDCLXXXI, MMMDCLXXXII, MMMDCLXXXIII, MMMDCLXXXIV, MMMDCLXXXV, MMMDCLXXXVI, MMMDCLXXXVII, MMMDCLXXXVIII, MMMDCLXXXIX, MMMDCXC, MMMDCXCII, MMMDCXCIII, MMMDCXCIV, MMMDCXCV, MMMDCXCVI, MMMDCXCVII, MMMDCXCVIII, MMMDCXCIX, MMMDCC, MMMDCCI, MMMDCCII, MMMDCCIII, MMMDCCIV, MMMDCCV, MMMDCCVI, MMMDCCVII, MMMDCCVIII, MMMDCCIX, MMMDCCX