Il numero romano MMMDCCLXXX nel sistema decimale vale: 3780.
MMMDCCLXXX in latino si scrive tria milia septingenti octoginta,
mentre in italiano tremilasettecentottanta.
MMMDCCLXI, MMMDCCLXII, MMMDCCLXIII, MMMDCCLXIV, MMMDCCLXV, MMMDCCLXVI, MMMDCCLXVII, MMMDCCLXVIII, MMMDCCLXIX, MMMDCCLXX, MMMDCCLXXI, MMMDCCLXXII, MMMDCCLXXIII, MMMDCCLXXIV, MMMDCCLXXV, MMMDCCLXXVI, MMMDCCLXXVII, MMMDCCLXXVIII, MMMDCCLXXIX, MMMDCCLXXXI, MMMDCCLXXXII, MMMDCCLXXXIII, MMMDCCLXXXIV, MMMDCCLXXXV, MMMDCCLXXXVI, MMMDCCLXXXVII, MMMDCCLXXXVIII, MMMDCCLXXXIX, MMMDCCXC, MMMDCCXCI, MMMDCCXCII, MMMDCCXCIII, MMMDCCXCIV, MMMDCCXCV, MMMDCCXCVI, MMMDCCXCVII, MMMDCCXCVIII, MMMDCCXCIX