809959 has 4 divisors (see below), whose sum is σ = 813240. Its totient is φ = 806680.

The previous prime is 809929. The next prime is 809981. The reversal of 809959 is 959908.

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

It is a cyclic number.

It is not a de Polignac number, because 809959 - 2⁹ = 809447 is a prime.

It is a Duffinian number.

809959 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1237 + ... + 1774.

It is an arithmetic number, because the mean of its divisors is an integer number (203310).

2⁸⁰⁹⁹⁵⁹ is an apocalyptic number.

809959 is a deficient number, since it is larger than the sum of its proper divisors (3281).

809959 is a wasteful number, since it uses less digits than its factorization.

809959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3280.

The product of its (nonzero) digits is 29160, while the sum is 40.

The square root of 809959 is about 899.9772219340. The cubic root of 809959 is about 93.2154023554.

The spelling of 809959 in words is "eight hundred nine thousand, nine hundred fifty-nine".