863665 has 16 divisors (see below), whose sum is σ = 1161216. Its totient is φ = 611200.

The previous prime is 863641. The next prime is 863671. The reversal of 863665 is 566368.

It is not a de Polignac number, because 863665 - 2⁵ = 863633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 863665.

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 15 ways as a sum of consecutive naturals, for example, 2064 + ... + 2446.

It is an arithmetic number, because the mean of its divisors is an integer number (72576).

2⁸⁶³⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

863665 is a deficient number, since it is larger than the sum of its proper divisors (297551).

863665 is a wasteful number, since it uses less digits than its factorization.

863665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440.

The product of its digits is 25920, while the sum is 34.

The square root of 863665 is about 929.3357843105. The cubic root of 863665 is about 95.2317518196.

The spelling of 863665 in words is "eight hundred sixty-three thousand, six hundred sixty-five".