18066997 has 4 divisors (see below), whose sum is σ = 19456780. Its totient is φ = 16677216.

The previous prime is 18066991. The next prime is 18067013. The reversal of 18066997 is 79966081.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2337841 + 15729156 = 1529^2 + 3966^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18066997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18066991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 694872 + ... + 694897.

It is an arithmetic number, because the mean of its divisors is an integer number (4864195).

Almost surely, 2^18066997 is an apocalyptic number.

It is an amenable number.

18066997 is a deficient number, since it is larger than the sum of its proper divisors (1389783).

18066997 is a wasteful number, since it uses less digits than its factorization.

18066997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1389782.

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 18066997 is about 4250.5290258978. The cubic root of 18066997 is about 262.3988883445.

The spelling of 18066997 in words is "eighteen million, sixty-six thousand, nine hundred ninety-seven".