320809 has 4 divisors (see below), whose sum is σ = 326916. Its totient is φ = 314704.

The previous prime is 320791. The next prime is 320821. The reversal of 320809 is 908023.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908023 = 727 ⋅1249.

It can be written as a sum of positive squares in 2 ways, for example, as 115600 + 205209 = 340^2 + 453^2 .

It is a cyclic number.

It is not a de Polignac number, because 320809 - 2¹³ = 312617 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 320809.

It is not an unprimeable number, because it can be changed into a prime (320839) 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, 2974 + ... + 3079.

It is an arithmetic number, because the mean of its divisors is an integer number (81729).

2³²⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

320809 is a deficient number, since it is larger than the sum of its proper divisors (6107).

320809 is an equidigital number, since it uses as much as digits as its factorization.

320809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6106.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 320809 is about 566.4000353107. The cubic root of 320809 is about 68.4566298003.

The spelling of 320809 in words is "three hundred twenty thousand, eight hundred nine".