18665718989 has 2 divisors, whose sum is σ = 18665718990. Its totient is φ = 18665718988.

The previous prime is 18665718971. The next prime is 18665718991. The reversal of 18665718989 is 98981756681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18586686889 + 79032100 = 136333^2 + 8890^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18665718989 is a prime.

Together with 18665718991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18665718289) 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, 9332859494 + 9332859495.

It is an arithmetic number, because the mean of its divisors is an integer number (9332859495).

Almost surely, 2^18665718989 is an apocalyptic number.

It is an amenable number.

18665718989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18665718989 is an equidigital number, since it uses as much as digits as its factorization.

18665718989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52254720, while the sum is 68.

The spelling of 18665718989 in words is "eighteen billion, six hundred sixty-five million, seven hundred eighteen thousand, nine hundred eighty-nine".