18660643 has 2 divisors, whose sum is σ = 18660644. Its totient is φ = 18660642.

The previous prime is 18660623. The next prime is 18660683. The reversal of 18660643 is 34606681.

It is a weak prime.

It is an emirp because it is prime and its reverse (34606681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18660643 - 2¹⁷ = 18529571 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18660599 and 18660608.

It is not a weakly prime, because it can be changed into another prime (18660623) 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 as a sum of consecutive naturals, namely, 9330321 + 9330322.

It is an arithmetic number, because the mean of its divisors is an integer number (9330322).

Almost surely, 2^18660643 is an apocalyptic number.

18660643 is a deficient number, since it is larger than the sum of its proper divisors (1).

18660643 is an equidigital number, since it uses as much as digits as its factorization.

18660643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 18660643 is about 4319.7966387320. The cubic root of 18660643 is about 265.2419435111.

The spelling of 18660643 in words is "eighteen million, six hundred sixty thousand, six hundred forty-three".