818861 has 4 divisors (see below), whose sum is σ = 832800. Its totient is φ = 804924.

The previous prime is 818837. The next prime is 818887. The reversal of 818861 is 168818.

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 a cyclic number.

It is not a de Polignac number, because 818861 - 2¹⁰ = 817837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (818821) 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, 6881 + ... + 6998.

It is an arithmetic number, because the mean of its divisors is an integer number (208200).

2⁸¹⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

818861 is a deficient number, since it is larger than the sum of its proper divisors (13939).

818861 is a wasteful number, since it uses less digits than its factorization.

818861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13938.

The product of its digits is 3072, while the sum is 32.

The square root of 818861 is about 904.9093877290. The cubic root of 818861 is about 93.5556590450. Note that the first 3 decimals are identical.

The spelling of 818861 in words is "eight hundred eighteen thousand, eight hundred sixty-one".