818905 has 4 divisors (see below), whose sum is σ = 982692. Its totient is φ = 655120.

The previous prime is 818897. The next prime is 818947. The reversal of 818905 is 509818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 118336 + 700569 = 344^2 + 837^2 .

It is not a de Polignac number, because 818905 - 2³ = 818897 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

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, 81886 + ... + 81895.

It is an arithmetic number, because the mean of its divisors is an integer number (245673).

2⁸¹⁸⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

818905 is a deficient number, since it is larger than the sum of its proper divisors (163787).

818905 is a wasteful number, since it uses less digits than its factorization.

818905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163786.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 818905 is about 904.9336992288. The cubic root of 818905 is about 93.5573346958.

The spelling of 818905 in words is "eight hundred eighteen thousand, nine hundred five".