18885666557 has 2 divisors, whose sum is σ = 18885666558. Its totient is φ = 18885666556.

The previous prime is 18885666539. The next prime is 18885666601. The reversal of 18885666557 is 75566658881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18866121316 + 19545241 = 137354^2 + 4421^2 .

It is a cyclic number.

It is not a de Polignac number, because 18885666557 - 2³⁰ = 17811924733 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18885666493 and 18885666502.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18885666257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9442833278 + 9442833279.

It is an arithmetic number, because the mean of its divisors is an integer number (9442833279).

Almost surely, 2^18885666557 is an apocalyptic number.

It is an amenable number.

18885666557 is a deficient number, since it is larger than the sum of its proper divisors (1).

18885666557 is an equidigital number, since it uses as much as digits as its factorization.

18885666557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768000, while the sum is 65.

The spelling of 18885666557 in words is "eighteen billion, eight hundred eighty-five million, six hundred sixty-six thousand, five hundred fifty-seven".