805209 has 4 divisors (see below), whose sum is σ = 1073616. Its totient is φ = 536804.

The previous prime is 805187. The next prime is 805213. The reversal of 805209 is 902508.

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 805209 - 2⁵ = 805177 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (805219) 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, 134199 + ... + 134204.

It is an arithmetic number, because the mean of its divisors is an integer number (268404).

2⁸⁰⁵²⁰⁹ is an apocalyptic number.

It is an amenable number.

805209 is a deficient number, since it is larger than the sum of its proper divisors (268407).

805209 is a wasteful number, since it uses less digits than its factorization.

805209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268406.

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

The square root of 805209 is about 897.3343858340. The cubic root of 805209 is about 93.0328245792.

The spelling of 805209 in words is "eight hundred five thousand, two hundred nine".