808640809 has 4 divisors (see below), whose sum is σ = 830496004. Its totient is φ = 786785616.

The previous prime is 808640773. The next prime is 808640867. The reversal of 808640809 is 908046808.

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

It can be written as a sum of positive squares in 2 ways, for example, as 395413225 + 413227584 = 19885^2 + 20328^2 .

It is a cyclic number.

It is not a de Polignac number, because 808640809 - 2⁷ = 808640681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (808640869) 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, 10927542 + ... + 10927615.

It is an arithmetic number, because the mean of its divisors is an integer number (207624001).

Almost surely, 2^808640809 is an apocalyptic number.

It is an amenable number.

808640809 is a deficient number, since it is larger than the sum of its proper divisors (21855195).

808640809 is a wasteful number, since it uses less digits than its factorization.

808640809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21855194.

The product of its (nonzero) digits is 110592, while the sum is 43.

The square root of 808640809 is about 28436.6103641063. The cubic root of 808640809 is about 931.6480620422.

The spelling of 808640809 in words is "eight hundred eight million, six hundred forty thousand, eight hundred nine".