16668081 has 6 divisors (see below), whose sum is σ = 24076130. Its totient is φ = 11112048.

The previous prime is 16668079. The next prime is 16668089. The reversal of 16668081 is 18086661.

It can be written as a sum of positive squares in only one way, i.e., 13395600 + 3272481 = 3660^2 + 1809^2 .

It is not a de Polignac number, because 16668081 - 2¹ = 16668079 is a prime.

It is a super-2 number, since 2×16668081² = 555649848445122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16668089) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 925996 + ... + 926013.

Almost surely, 2^16668081 is an apocalyptic number.

It is an amenable number.

16668081 is a deficient number, since it is larger than the sum of its proper divisors (7408049).

16668081 is a wasteful number, since it uses less digits than its factorization.

16668081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1852015 (or 1852012 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 16668081 is about 4082.6561207136. The cubic root of 16668081 is about 255.4437027066.

The spelling of 16668081 in words is "sixteen million, six hundred sixty-eight thousand, eighty-one".