18966320918639 has 2 divisors, whose sum is σ = 18966320918640. Its totient is φ = 18966320918638.

The previous prime is 18966320918609. The next prime is 18966320918717. The reversal of 18966320918639 is 93681902366981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18966320918639 - 2²⁴ = 18966304141423 is a prime.

It is a super-2 number, since 2×18966320918639² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18966320918609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9483160459319 + 9483160459320.

It is an arithmetic number, because the mean of its divisors is an integer number (9483160459320).

Almost surely, 2^{18966320918639} is an apocalyptic number.

18966320918639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18966320918639 is an equidigital number, since it uses as much as digits as its factorization.

18966320918639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181398528, while the sum is 71.

The spelling of 18966320918639 in words is "eighteen trillion, nine hundred sixty-six billion, three hundred twenty million, nine hundred eighteen thousand, six hundred thirty-nine".