863809 has 4 divisors (see below), whose sum is σ = 875716. Its totient is φ = 851904.

The previous prime is 863803. The next prime is 863833. The reversal of 863809 is 908368.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 680625 + 183184 = 825^2 + 428^2 .

It is a cyclic number.

It is not a de Polignac number, because 863809 - 2³ = 863801 is a prime.

It is a Duffinian number.

863809 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (863801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5844 + ... + 5989.

It is an arithmetic number, because the mean of its divisors is an integer number (218929).

2⁸⁶³⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

863809 is a deficient number, since it is larger than the sum of its proper divisors (11907).

863809 is a wasteful number, since it uses less digits than its factorization.

863809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11906.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 863809 is about 929.4132557695. The cubic root of 863809 is about 95.2370442305.

The spelling of 863809 in words is "eight hundred sixty-three thousand, eight hundred nine".