812805 has 16 divisors (see below), whose sum is σ = 1486464. Its totient is φ = 371520.

The previous prime is 812761. The next prime is 812807. The reversal of 812805 is 508218.

It is not a de Polignac number, because 812805 - 2¹¹ = 810757 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (812807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3766 + ... + 3975.

It is an arithmetic number, because the mean of its divisors is an integer number (92904).

2⁸¹²⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

812805 is a deficient number, since it is larger than the sum of its proper divisors (673659).

812805 is a wasteful number, since it uses less digits than its factorization.

812805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7756.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 812805 is about 901.5569865516. The cubic root of 812805 is about 93.3244535203.

The spelling of 812805 in words is "eight hundred twelve thousand, eight hundred five".