16865640009 has 12 divisors (see below), whose sum is σ = 24364546752. Its totient is φ = 11242344600.

The previous prime is 16865639981. The next prime is 16865640013. The reversal of 16865640009 is 90004656861.

16865640009 is a `hidden beast` number, since 1 + 6 + 86 + 564 + 0 + 0 + 0 + 9 = 666.

It is not a de Polignac number, because 16865640009 - 2²⁰ = 16864591433 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (16865640049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39757 + ... + 187914.

It is an arithmetic number, because the mean of its divisors is an integer number (2030378896).

Almost surely, 2^16865640009 is an apocalyptic number.

It is an amenable number.

16865640009 is a deficient number, since it is larger than the sum of its proper divisors (7498906743).

16865640009 is a wasteful number, since it uses less digits than its factorization.

16865640009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235908 (or 235905 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 16865640009 in words is "sixteen billion, eight hundred sixty-five million, six hundred forty thousand, nine".