18685368666857 has 2 divisors, whose sum is σ = 18685368666858. Its totient is φ = 18685368666856.

The previous prime is 18685368666773. The next prime is 18685368666883. The reversal of 18685368666857 is 75866686358681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14782456281616 + 3902912385241 = 3844796^2 + 1975579^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18685368666857 is a prime.

It is a super-2 number, since 2×18685368666857² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18685368660857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9342684333428 + 9342684333429.

It is an arithmetic number, because the mean of its divisors is an integer number (9342684333429).

Almost surely, 2^{18685368666857} is an apocalyptic number.

It is an amenable number.

18685368666857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18685368666857 is an equidigital number, since it uses as much as digits as its factorization.

18685368666857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16721510400, while the sum is 83.

The spelling of 18685368666857 in words is "eighteen trillion, six hundred eighty-five billion, three hundred sixty-eight million, six hundred sixty-six thousand, eight hundred fifty-seven".