18887689 has 2 divisors, whose sum is σ = 18887690. Its totient is φ = 18887688.

The previous prime is 18887683. The next prime is 18887699. The reversal of 18887689 is 98678881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 1247689 = 4200^2 + 1117^2 .

It is a cyclic number.

It is not a de Polignac number, because 18887689 - 2³ = 18887681 is a prime.

It is not a weakly prime, because it can be changed into another prime (18887681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9443844 + 9443845.

It is an arithmetic number, because the mean of its divisors is an integer number (9443845).

Almost surely, 2^18887689 is an apocalyptic number.

It is an amenable number.

18887689 is a deficient number, since it is larger than the sum of its proper divisors (1).

18887689 is an equidigital number, since it uses as much as digits as its factorization.

18887689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1548288, while the sum is 55.

The square root of 18887689 is about 4345.9968936942. The cubic root of 18887689 is about 266.3133520550.

The spelling of 18887689 in words is "eighteen million, eight hundred eighty-seven thousand, six hundred eighty-nine".