811665009 has 32 divisors (see below), whose sum is σ = 1320806400. Its totient is φ = 490335120.

The previous prime is 811665007. The next prime is 811665011. The reversal of 811665009 is 900566118.

It is an interprime number because it is at equal distance from previous prime (811665007) and next prime (811665011).

It is not a de Polignac number, because 811665009 - 2¹ = 811665007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (811665007) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 22597 + ... + 46194.

It is an arithmetic number, because the mean of its divisors is an integer number (41275200).

Almost surely, 2^811665009 is an apocalyptic number.

It is an amenable number.

811665009 is a deficient number, since it is larger than the sum of its proper divisors (509141391).

811665009 is a wasteful number, since it uses less digits than its factorization.

811665009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68842 (or 68836 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 811665009 is about 28489.7351514541. The cubic root of 811665009 is about 932.8080270031.

The spelling of 811665009 in words is "eight hundred eleven million, six hundred sixty-five thousand, nine".