Il numero romano MDCI nel sistema decimale vale: 1601.
MDCI in latino si scrive mille sescenti unus,
mentre in italiano milleseicentouno.
MDLXXXII, MDLXXXIII, MDLXXXIV, MDLXXXV, MDLXXXVI, MDLXXXVII, MDLXXXVIII, MDLXXXIX, MDXC, MDXCI, MDXCII, MDXCIII, MDXCIV, MDXCV, MDXCVI, MDXCVII, MDXCVIII, MDXCIX, MDC, MDCII, MDCIII, MDCIV, MDCV, MDCVI, MDCVII, MDCVIII, MDCIX, MDCX, MDCXI, MDCXII, MDCXIII, MDCXIV, MDCXV, MDCXVI, MDCXVII, MDCXVIII, MDCXIX, MDCXX