18642681 has 12 divisors (see below), whose sum is σ = 27196260. Its totient is φ = 12304800.

The previous prime is 18642647. The next prime is 18642703. The reversal of 18642681 is 18624681.

18642681 is a `hidden beast` number, since 1 + 8 + 642 + 6 + 8 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11799225 + 6843456 = 3435^2 + 2616^2 .

It is not a de Polignac number, because 18642681 - 2¹³ = 18634489 is a prime.

It is a super-2 number, since 2×18642681² = 695099109735522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18642601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9346 + ... + 11163.

It is an arithmetic number, because the mean of its divisors is an integer number (2266355).

Almost surely, 2^18642681 is an apocalyptic number.

It is an amenable number.

18642681 is a deficient number, since it is larger than the sum of its proper divisors (8553579).

18642681 is a wasteful number, since it uses less digits than its factorization.

18642681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20616 (or 20613 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 18642681 is about 4317.7171051379. The cubic root of 18642681 is about 265.1568123745.

The spelling of 18642681 in words is "eighteen million, six hundred forty-two thousand, six hundred eighty-one".