864859 has 4 divisors (see below), whose sum is σ = 885016. Its totient is φ = 844704.

The previous prime is 864817. The next prime is 864883. The reversal of 864859 is 958468.

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

It is a cyclic number.

It is not a de Polignac number, because 864859 - 2¹¹ = 862811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (864359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10014 + ... + 10099.

It is an arithmetic number, because the mean of its divisors is an integer number (221254).

2⁸⁶⁴⁸⁵⁹ is an apocalyptic number.

864859 is a deficient number, since it is larger than the sum of its proper divisors (20157).

864859 is a wasteful number, since it uses less digits than its factorization.

864859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20156.

The product of its digits is 69120, while the sum is 40.

The square root of 864859 is about 929.9779567280. The cubic root of 864859 is about 95.2756169574.

The spelling of 864859 in words is "eight hundred sixty-four thousand, eight hundred fifty-nine".