18966817 has 2 divisors, whose sum is σ = 18966818. Its totient is φ = 18966816.

The previous prime is 18966797. The next prime is 18966821. The reversal of 18966817 is 71866981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18740241 + 226576 = 4329^2 + 476^2 .

It is a cyclic number.

It is not a de Polignac number, because 18966817 - 2²³ = 10578209 is a prime.

It is a super-2 number, since 2×18966817² = 719480294222978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18966877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9483408 + 9483409.

It is an arithmetic number, because the mean of its divisors is an integer number (9483409).

Almost surely, 2^18966817 is an apocalyptic number.

It is an amenable number.

18966817 is a deficient number, since it is larger than the sum of its proper divisors (1).

18966817 is an equidigital number, since it uses as much as digits as its factorization.

18966817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 18966817 is about 4355.0909290163. The cubic root of 18966817 is about 266.6847312415.

The spelling of 18966817 in words is "eighteen million, nine hundred sixty-six thousand, eight hundred seventeen".