520809 has 8 divisors (see below), whose sum is σ = 731040. Its totient is φ = 328896.

The previous prime is 520787. The next prime is 520813. The reversal of 520809 is 908025.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 520809 - 2⁹ = 520297 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (520889) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4512 + ... + 4625.

It is an arithmetic number, because the mean of its divisors is an integer number (91380).

2⁵²⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

520809 is a deficient number, since it is larger than the sum of its proper divisors (210231).

520809 is a wasteful number, since it uses less digits than its factorization.

520809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9159.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 520809 is about 721.6709776623. The cubic root of 520809 is about 80.4561957070.

The spelling of 520809 in words is "five hundred twenty thousand, eight hundred nine".