864889 has 4 divisors (see below), whose sum is σ = 869200. Its totient is φ = 860580.

The previous prime is 864887. The next prime is 864901. The reversal of 864889 is 988468.

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 864889 - 2¹ = 864887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (864883) 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, 1839 + ... + 2260.

It is an arithmetic number, because the mean of its divisors is an integer number (217300).

2⁸⁶⁴⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

864889 is a deficient number, since it is larger than the sum of its proper divisors (4311).

864889 is a wasteful number, since it uses less digits than its factorization.

864889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4310.

The product of its digits is 110592, while the sum is 43.

The square root of 864889 is about 929.9940860027. The cubic root of 864889 is about 95.2767185764.

The spelling of 864889 in words is "eight hundred sixty-four thousand, eight hundred eighty-nine".