347

347 is a natural number that comes after 346 and before 348. In mathematics, it is a prime number and the 69th prime. It is also a safe prime, since (347 − 1) / 2 = 173 is prime. Because it is congruent to 3 modulo 4, 347 cannot be expressed as a sum of two squares. The digits sum to 14, so 347 is not divisible by 3. In base 2 it is 101011011, and in hexadecimal it is 0x015B. In Roman numerals it is written CCCXLVII.

347’s status as a prime carries typical number-theoretic implications, such as its lack of nontrivial divisors. It is also part of the sequence of primes and, as a safe prime, has applications in certain cryptographic constructions where primes p with (p−1)/2 also prime are desirable. Its modular properties (being 3 mod 4) place it outside the class of primes that can be represented as a sum of two squares.

In real-world usage, 347 is known primarily as an area code for New York City. It overlays the 718 area code and covers portions of Brooklyn, Queens, the Bronx, and Staten Island. Numbers assigned 347 are common for both mobile and landline services in that region, often used in combination with other NYC area codes such as 718 and 929. The code is part of the broader telecommunications infrastructure of the New York metropolitan area.