631

631 is a natural number that follows 630 and precedes 632. In mathematics, 631 is a prime number. It is odd and congruent to 3 modulo 4, which means it cannot be expressed as a sum of two squares.

In common representations, 631 is written in binary as 1001110111 and in Roman numerals as DCXXXI. As a prime number, its only positive divisors are 1 and 631.

In telecommunications, 631 is the North American area code assigned to eastern Long Island, New York, serving parts of Suffolk County. Area codes are part of the North American Numbering Plan and help route telephone calls.

Beyond its role as a numeric identifier, 631 may appear in various cataloging or sequential contexts, but it is primarily recognized for its mathematical property as a prime number and for its use as an area code in the New York region.