340

340 is a natural number that follows 339 and precedes 341. It is even and composite, with prime factorization 2^2 · 5 · 17. This means 340 is divisible by 1, 2, 4, 5, 10, 17, 20, 34, 68, 85, 170, and 340.

340 is an abundant number, since the sum of its positive divisors, including itself, equals 756, which is greater than 2 × 340 (680). Its proper divisors sum to 416. The prime factors 2, 5, and 17 are all distinct, making 340 have three distinct prime factors.

In base representations, 340 is written as 101010100 in binary, 524 in octal, and 0x154 in hexadecimal. In Roman numerals it is CCCXL. The decimal digits sum to 7, and the number is not a prime, not a square, and not a triangular number.

As a calendar year, 340 CE is a year in late antiquity. The number 340 also appears in various cataloging and numbering systems as a code or identifier, separate from its mathematical properties.