813905 has 16 divisors (see below), whose sum is σ = 1036800. Its totient is φ = 612480.

The previous prime is 813893. The next prime is 813907. The reversal of 813905 is 509318.

813905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-813905 is a prime.

It is an Ulam number.

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813905.

It is not an unprimeable number, because it can be changed into a prime (813907) 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, 9101 + ... + 9189.

It is an arithmetic number, because the mean of its divisors is an integer number (64800).

2⁸¹³⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

813905 is a deficient number, since it is larger than the sum of its proper divisors (222895).

813905 is a wasteful number, since it uses less digits than its factorization.

813905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 813905 is about 902.1668360121. The cubic root of 813905 is about 93.3665343899.

The spelling of 813905 in words is "eight hundred thirteen thousand, nine hundred five".