16666091 has 4 divisors (see below), whose sum is σ = 17948112. Its totient is φ = 15384072.

The previous prime is 16666081. The next prime is 16666093. The reversal of 16666091 is 19066661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16666091 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16666093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 640991 + ... + 641016.

It is an arithmetic number, because the mean of its divisors is an integer number (4487028).

Almost surely, 2^16666091 is an apocalyptic number.

16666091 is a deficient number, since it is larger than the sum of its proper divisors (1282021).

16666091 is a wasteful number, since it uses less digits than its factorization.

16666091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1282020.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 16666091 is about 4082.4123995501. The cubic root of 16666091 is about 255.4335365053.

The spelling of 16666091 in words is "sixteen million, six hundred sixty-six thousand, ninety-one".