219

219 is a natural number that follows 218 and precedes 220. It is odd and composite, with prime factorization 3 × 73, making it a semiprime and square-free. The positive divisors of 219 are 1, 3, 73, and 219. In Roman numerals it is written as CCXIX. In base representations it appears as 11011011 in binary, 0333 in octal, and DB in hexadecimal.

In mathematical terms, 219 is divisible by 3 (the sum of its digits is 12). It is congruent to 0 modulo 3 and to 3 modulo 4. Its status as a product of two distinct primes makes it a useful example of a square-free semiprime in number theory discussions. Its various Base- systems representations (binary, octal, hex) illustrate straightforward conversion steps.

219 is also used as an area code in the North American Numbering Plan, serving Northwest Indiana, including cities such as Gary, Hammond, East Chicago, and Michigan City. This regional designation has been in use for decades within the dialing plan of the United States.

In the calendar, the 219th day of the year in the Gregorian system is August 7 in common years and August 6 in leap years, marking a mid-summer position in most years.

Historically, the year AD 219 falls within the era of the Roman Empire, occurring during the reign of Emperor Elagabalus, and is part of the broader period of the Severan dynasty.