18940787689 has 2 divisors, whose sum is σ = 18940787690. Its totient is φ = 18940787688.

The previous prime is 18940787683. The next prime is 18940787713. The reversal of 18940787689 is 98678704981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15504483289 + 3436304400 = 124517^2 + 58620^2 .

It is a cyclic number.

It is not a de Polignac number, because 18940787689 - 2¹⁷ = 18940656617 is a prime.

It is not a weakly prime, because it can be changed into another prime (18940787683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9470393844 + 9470393845.

It is an arithmetic number, because the mean of its divisors is an integer number (9470393845).

Almost surely, 2^18940787689 is an apocalyptic number.

It is an amenable number.

18940787689 is a deficient number, since it is larger than the sum of its proper divisors (1).

18940787689 is an equidigital number, since it uses as much as digits as its factorization.

18940787689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48771072, while the sum is 67.

The spelling of 18940787689 in words is "eighteen billion, nine hundred forty million, seven hundred eighty-seven thousand, six hundred eighty-nine".