16804391666 has 8 divisors (see below), whose sum is σ = 25304668380. Its totient is φ = 8369502208.

The previous prime is 16804391663. The next prime is 16804391687. The reversal of 16804391666 is 66619340861.

It can be written as a sum of positive squares in 2 ways, for example, as 16803677641 + 714025 = 129629^2 + 845^2 .

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

It is not an unprimeable number, because it can be changed into a prime (16804391663) 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, 16346171 + ... + 16347198.

Almost surely, 2^16804391666 is an apocalyptic number.

16804391666 is a deficient number, since it is larger than the sum of its proper divisors (8500276714).

16804391666 is a wasteful number, since it uses less digits than its factorization.

16804391666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32693628.

The product of its (nonzero) digits is 1119744, while the sum is 50.

The spelling of 16804391666 in words is "sixteen billion, eight hundred four million, three hundred ninety-one thousand, six hundred sixty-six".