6891

6891 is a natural number that follows 6890 and precedes 6892. It is an odd composite number.

Prime factorization: 6891 = 3 × 2297, where 2297 is prime; hence 6891 is a semiprime. The factorization shows it is divisible by 3, with quotient 2297.

In base representations, 6891 has several common forms. Its binary representation is 1101011101011_2. In hexadecimal, it is 1AEB_16, and in octal it is 15353_8.

Digit sums and modular properties provide quick tests of its divisibility. The sum of digits is 6 + 8 + 9 + 1 = 24, so 6891 is divisible by 3 but not by 9. It is not divisible by 5, and mod 7 gives a remainder of 3, so 6891 ≡ 3 (mod 7).

A nearby square observation is that 83^2 = 6889, so 6891 is 83^2 + 2. This places it very close to a perfect square.

In mathematical contexts, 6891 is frequently encountered as an example of a semiprime— a product of two primes— and is sometimes used in elementary discussions of factorization and modular arithmetic. As a composite number with a small prime factor and a relatively large cofactor, it illustrates basic properties of divisibility, base representations, and nearby-square relationships.