341

341 is the natural number that follows 340 and precedes 342. It is odd and composite. The prime factorization of 341 is 11 × 31, making it a semiprime. Its divisors are 1, 11, 31, and 341.

In number theory, 341 is notable as the smallest Fermat pseudoprime to base 2, since 2^340 is congruent to 1 modulo 341 even though 341 is not prime. In common numeral representations, 341 equals 0b101010101 in binary and 0x155 in hexadecimal. Its sum of divisors is 384, and the sum of proper divisors is 43, which makes 341 a deficient number.

In astronomy, 341 Ingeborg is a main-belt asteroid. It is one of many minor planets designated by a number and a name.

In Roman numerals, 341 is written as CCCXLI.