1086

1086 is a natural number that comes after 1085 and before 1087. It is even and composite, with prime factorization 2 × 3 × 181. Because it has three distinct prime factors, it is a sphenic number. In decimal, its digits sum to 15; it is divisible by 3 but not by 9. In binary it is 10000111110, and in hexadecimal it is 0x43E. In Roman numerals it is written MLXXXVI. The decimal value 1086 also corresponds to Unicode code point U+043E, the Cyrillic small letter o.

1086 as a year is notable primarily for the completion of the Domesday Book in England. Commissioned by William the Conqueror in 1085 to survey landholding and resources for taxation, the work was largely completed in 1086. The Domesday Book records landowners, holdings, values, and resources across much of England and is divided into Great Domesday and Little Domesday. It has become a key source for understanding late Anglo-Saxon and Norman England and is preserved in manuscript form in national and regional archives, with published and digitized editions available for study.