509209 has 4 divisors (see below), whose sum is σ = 511360. Its totient is φ = 507060.

The previous prime is 509203. The next prime is 509221. The reversal of 509209 is 902905.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 509209 - 2¹⁷ = 378137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509203) 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, 669 + ... + 1210.

It is an arithmetic number, because the mean of its divisors is an integer number (127840).

2⁵⁰⁹²⁰⁹ is an apocalyptic number.

It is an amenable number.

509209 is a deficient number, since it is larger than the sum of its proper divisors (2151).

509209 is a wasteful number, since it uses less digits than its factorization.

509209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2150.

The product of its (nonzero) digits is 810, while the sum is 25.

The square root of 509209 is about 713.5888171770. The cubic root of 509209 is about 79.8543704781.

The spelling of 509209 in words is "five hundred nine thousand, two hundred nine".