18966643 has 2 divisors, whose sum is σ = 18966644. Its totient is φ = 18966642.

The previous prime is 18966613. The next prime is 18966707. The reversal of 18966643 is 34666981.

It is a weak prime.

It is an emirp because it is prime and its reverse (34666981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18966643 - 2¹⁷ = 18835571 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18966643.

It is not a weakly prime, because it can be changed into another prime (18966613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9483321 + 9483322.

It is an arithmetic number, because the mean of its divisors is an integer number (9483322).

Almost surely, 2^18966643 is an apocalyptic number.

18966643 is a deficient number, since it is larger than the sum of its proper divisors (1).

18966643 is an equidigital number, since it uses as much as digits as its factorization.

18966643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 43.

The square root of 18966643 is about 4355.0709523497. The cubic root of 18966643 is about 266.6839157245.

The spelling of 18966643 in words is "eighteen million, nine hundred sixty-six thousand, six hundred forty-three".