864891 has 16 divisors (see below), whose sum is σ = 1297920. Its totient is φ = 569160.

The previous prime is 864887. The next prime is 864901. The reversal of 864891 is 198468.

It is a happy number.

864891 is a `hidden beast` number, since 8 + 648 + 9 + 1 = 666.

It is not a de Polignac number, because 864891 - 2² = 864887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (864811) 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, 2626 + ... + 2936.

It is an arithmetic number, because the mean of its divisors is an integer number (81120).

2⁸⁶⁴⁸⁹¹ is an apocalyptic number.

864891 is a deficient number, since it is larger than the sum of its proper divisors (433029).

864891 is a wasteful number, since it uses less digits than its factorization.

864891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423 (or 417 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 864891 is about 929.9951612777. The cubic root of 864891 is about 95.2767920168.

The spelling of 864891 in words is "eight hundred sixty-four thousand, eight hundred ninety-one".