Il numero romano MCCLXI nel sistema decimale vale: 1261.
MCCLXI in latino si scrive mille ducenti sexaginta unus,
mentre in italiano milleduecentosessantuno.
MCCXLII, MCCXLIII, MCCXLIV, MCCXLV, MCCXLVI, MCCXLVII, MCCXLVIII, MCCXLIX, MCCL, MCCLI, MCCLII, MCCLIII, MCCLIV, MCCLV, MCCLVI, MCCLVII, MCCLVIII, MCCLIX, MCCLX, MCCLXII, MCCLXIII, MCCLXIV, MCCLXV, MCCLXVI, MCCLXVII, MCCLXVIII, MCCLXIX, MCCLXX, MCCLXXI, MCCLXXII, MCCLXXIII, MCCLXXIV, MCCLXXV, MCCLXXVI, MCCLXXVII, MCCLXXVIII, MCCLXXIX, MCCLXXX