Il numero romano CLXXXI nel sistema decimale vale: 181.
CLXXXI in latino si scrive centum octoginta unus,
mentre in italiano centottantuno.
CLXII, CLXIII, CLXIV, CLXV, CLXVI, CLXVII, CLXVIII, CLXIX, CLXX, CLXXI, CLXXII, CLXXIII, CLXXIV, CLXXV, CLXXVI, CLXXVII, CLXXVIII, CLXXIX, CLXXX, CLXXXII, CLXXXIII, CLXXXIV, CLXXXV, CLXXXVI, CLXXXVII, CLXXXVIII, CLXXXIX, CXC, CXCI, CXCII, CXCIII, CXCIV, CXCV, CXCVI, CXCVII, CXCVIII, CXCIX, CC