6805 has 4 divisors (see below), whose sum is σ = 8172. Its totient is φ = 5440.

The previous prime is 6803. The next prime is 6823. The reversal of 6805 is 5086.

6805 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5086 = 2 ⋅2543.

It can be written as a sum of positive squares in 2 ways, for example, as 1764 + 5041 = 42^2 + 71^2 .

It is not a de Polignac number, because 6805 - 2¹ = 6803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6803) 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, 676 + ... + 685.

It is an arithmetic number, because the mean of its divisors is an integer number (2043).

2⁶⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

6805 is a deficient number, since it is larger than the sum of its proper divisors (1367).

6805 is a wasteful number, since it uses less digits than its factorization.

6805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 6805 is about 82.4924238946. The cubic root of 6805 is about 18.9500070778.

Subtracting from 6805 its sum of digits (19), we obtain a triangular number (6786 = T₁₁₆).

The spelling of 6805 in words is "six thousand, eight hundred five".