Il numero romano MDCCCLXVI nel sistema decimale vale: 1866.
MDCCCLXVI in latino si scrive mille octingenti sexaginta sex,
mentre in italiano milleottocentosessantasei.
MDCCCXLVII, MDCCCXLVIII, MDCCCXLIX, MDCCCL, MDCCCLI, MDCCCLII, MDCCCLIII, MDCCCLIV, MDCCCLV, MDCCCLVI, MDCCCLVII, MDCCCLVIII, MDCCCLIX, MDCCCLX, MDCCCLXI, MDCCCLXII, MDCCCLXIII, MDCCCLXIV, MDCCCLXV, MDCCCLXVII, MDCCCLXVIII, MDCCCLXIX, MDCCCLXX, MDCCCLXXI, MDCCCLXXII, MDCCCLXXIII, MDCCCLXXIV, MDCCCLXXV, MDCCCLXXVI, MDCCCLXXVII, MDCCCLXXVIII, MDCCCLXXIX, MDCCCLXXX, MDCCCLXXXI, MDCCCLXXXII, MDCCCLXXXIII, MDCCCLXXXIV, MDCCCLXXXV