16566681 has 8 divisors (see below), whose sum is σ = 22153600. Its totient is φ = 11012112.

The previous prime is 16566637. The next prime is 16566691. The reversal of 16566681 is 18666561.

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

It is not a de Polignac number, because 16566681 - 2⁷ = 16566553 is a prime.

It is a super-2 number, since 2×16566681² = 548909838711522, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16566611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6865 + ... + 8958.

It is an arithmetic number, because the mean of its divisors is an integer number (2769200).

Almost surely, 2^16566681 is an apocalyptic number.

It is an amenable number.

16566681 is a deficient number, since it is larger than the sum of its proper divisors (5586919).

16566681 is a wasteful number, since it uses less digits than its factorization.

16566681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16175.

The product of its digits is 51840, while the sum is 39.

The square root of 16566681 is about 4070.2187901881. The cubic root of 16566681 is about 254.9246528637.

The spelling of 16566681 in words is "sixteen million, five hundred sixty-six thousand, six hundred eighty-one".