810813 has 4 divisors (see below), whose sum is σ = 1081088. Its totient is φ = 540540.

The previous prime is 810809. The next prime is 810839. The reversal of 810813 is 318018.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 810813 - 2² = 810809 is a prime.

It is a D-number.

It is a Duffinian number.

810813 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 810813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135133 + ... + 135138.

It is an arithmetic number, because the mean of its divisors is an integer number (270272).

2⁸¹⁰⁸¹³ is an apocalyptic number.

It is an amenable number.

810813 is a deficient number, since it is larger than the sum of its proper divisors (270275).

810813 is a wasteful number, since it uses less digits than its factorization.

810813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270274.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 810813 is about 900.4515533886. The cubic root of 810813 is about 93.2481521579.

The spelling of 810813 in words is "eight hundred ten thousand, eight hundred thirteen".