809664985 has 8 divisors (see below), whose sum is σ = 981218376. Its totient is φ = 641318400.

The previous prime is 809664979. The next prime is 809664997. The reversal of 809664985 is 589466908.

It can be written as a sum of positive squares in 4 ways, for example, as 64593369 + 745071616 = 8037^2 + 27296^2 .

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

It is not a de Polignac number, because 809664985 - 2⁹ = 809664473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 801144 + ... + 802153.

It is an arithmetic number, because the mean of its divisors is an integer number (122652297).

Almost surely, 2^809664985 is an apocalyptic number.

It is an amenable number.

809664985 is a deficient number, since it is larger than the sum of its proper divisors (171553391).

809664985 is a wasteful number, since it uses less digits than its factorization.

809664985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1603403.

The product of its (nonzero) digits is 3732480, while the sum is 55.

The square root of 809664985 is about 28454.6127192060. The cubic root of 809664985 is about 932.0412193114.

The spelling of 809664985 in words is "eight hundred nine million, six hundred sixty-four thousand, nine hundred eighty-five".