805 has 8 divisors (see below), whose sum is σ = 1152. Its totient is φ = 528.

The previous prime is 797. The next prime is 809. The reversal of 805 is 508.

805 = 4² + 5² + ... + 13².

805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 805 - 2³ = 797 is a prime.

It is a Duffinian number.

805 is a lucky number.

It is a plaindrome in base 8, base 13 and base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24 + ... + 46.

It is an arithmetic number, because the mean of its divisors is an integer number (144).

It is an amenable number.

805 is a deficient number, since it is larger than the sum of its proper divisors (347).

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

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

The sum of its prime factors is 35.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 805 is about 28.3725219182. The cubic root of 805 is about 9.3024774685.

Adding to 805 its sum of digits (13), we get a palindrome (818).

It can be divided in two parts, 80 and 5, that multiplied together give a square (400 = 20²).

The spelling of 805 in words is "eight hundred five", and thus it is an aban number and an oban number.