864855 has 12 divisors (see below), whose sum is σ = 1499160. Its totient is φ = 461232.

The previous prime is 864817. The next prime is 864883. The reversal of 864855 is 558468.

It is a happy number.

864855 is a `hidden beast` number, since 8 + 648 + 5 + 5 = 666.

It is not a de Polignac number, because 864855 - 2¹² = 860759 is a prime.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 9565 + ... + 9654.

It is an arithmetic number, because the mean of its divisors is an integer number (124930).

2⁸⁶⁴⁸⁵⁵ is an apocalyptic number.

864855 is a deficient number, since it is larger than the sum of its proper divisors (634305).

864855 is a wasteful number, since it uses less digits than its factorization.

864855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19230 (or 19227 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 864855 is about 929.9758061369. The cubic root of 864855 is about 95.2754700729.

It can be divided in two parts, 864 and 855, that multiplied together give a triangular number (738720 = T₁₂₁₅).

The spelling of 864855 in words is "eight hundred sixty-four thousand, eight hundred fifty-five".