6865 has 4 divisors (see below), whose sum is σ = 8244. Its totient is φ = 5488.

The previous prime is 6863. The next prime is 6869. The reversal of 6865 is 5686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5686 = 2 ⋅2843.

It can be written as a sum of positive squares in 2 ways, for example, as 5184 + 1681 = 72^2 + 41^2 .

It is a cyclic number.

It is not a de Polignac number, because 6865 - 2¹ = 6863 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 682 + ... + 691.

It is an arithmetic number, because the mean of its divisors is an integer number (2061).

2⁶⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

6865 is a deficient number, since it is larger than the sum of its proper divisors (1379).

6865 is a wasteful number, since it uses less digits than its factorization.

6865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378.

The product of its digits is 1440, while the sum is 25.

The square root of 6865 is about 82.8552955459. The cubic root of 6865 is about 19.0055385515.

The spelling of 6865 in words is "six thousand, eight hundred sixty-five".