863865 has 32 divisors (see below), whose sum is σ = 1574400. Its totient is φ = 454896.

The previous prime is 863851. The next prime is 863867. The reversal of 863865 is 568368.

It is not a de Polignac number, because 863865 - 2⁵ = 863833 is a prime.

863865 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (863867) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10896 + ... + 10974.

It is an arithmetic number, because the mean of its divisors is an integer number (49200).

2⁸⁶³⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

863865 is a deficient number, since it is larger than the sum of its proper divisors (710535).

863865 is an frugal number, since it uses more digits than its factorization.

863865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 87 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 863865 is about 929.4433818152. The cubic root of 863865 is about 95.2391022314.

It can be divided in two parts, 863 and 865, that added together give a cube (1728 = 12³).

The spelling of 863865 in words is "eight hundred sixty-three thousand, eight hundred sixty-five".