Il numero romano MDCXX nel sistema decimale vale: 1620.
MDCXX in latino si scrive mille sescenti viginti,
mentre in italiano milleseicentoventi.
MDCI, MDCII, MDCIII, MDCIV, MDCV, MDCVI, MDCVII, MDCVIII, MDCIX, MDCX, MDCXI, MDCXII, MDCXIII, MDCXIV, MDCXV, MDCXVI, MDCXVII, MDCXVIII, MDCXIX, MDCXXI, MDCXXII, MDCXXIII, MDCXXIV, MDCXXV, MDCXXVI, MDCXXVII, MDCXXVIII, MDCXXIX, MDCXXX, MDCXXXI, MDCXXXII, MDCXXXIII, MDCXXXIV, MDCXXXV, MDCXXXVI, MDCXXXVII, MDCXXXVIII, MDCXXXIX