869

869 is a natural number that follows 868 and precedes 870. In mathematics, it is an odd composite number equal to the product of the primes 11 and 79, making it a semiprime. Its four positive divisors are 1, 11, 79, and 869.

In base representations, 869 is 1101100101 in binary and 0x365 in hexadecimal. Its Roman numeral representation is DCCCLXIX. It is not a square or a cube, and it lies between the triangular numbers T41 (861) and T42 (903).

As a year, 869 CE marks a point in the late ninth century within historical timelines. Records from that period are uneven across different regions, so specific events attributed to the year can vary by source. The designation 869 is primarily used in chronological and mathematical contexts rather than to denote a single widely recognized historical milestone.

In summary, 869 is a semiprime with straightforward representations in several numeral systems, a definite position in the sequence of natural numbers, and a modest role as a calendar year in historical chronology.