18685258681 has 2 divisors, whose sum is σ = 18685258682. Its totient is φ = 18685258680.

The previous prime is 18685258679. The next prime is 18685258723.

18685258681 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18112853056 + 572405625 = 134584^2 + 23925^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 18685258681 - 2¹ = 18685258679 is a prime.

It is a super-2 number, since 2×18685258681² (a number of 21 digits) contains 22 as substring.

Together with 18685258679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18685258621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9342629340 + 9342629341.

It is an arithmetic number, because the mean of its divisors is an integer number (9342629341).

Almost surely, 2^18685258681 is an apocalyptic number.

It is an amenable number.

18685258681 is a deficient number, since it is larger than the sum of its proper divisors (1).

18685258681 is an equidigital number, since it uses as much as digits as its factorization.

18685258681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7372800, while the sum is 58.

The spelling of 18685258681 in words is "eighteen billion, six hundred eighty-five million, two hundred fifty-eight thousand, six hundred eighty-one".