18266681 has 4 divisors (see below), whose sum is σ = 18275364. Its totient is φ = 18258000.

The previous prime is 18266671. The next prime is 18266693. The reversal of 18266681 is 18666281.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 6295081 + 11971600 = 2509^2 + 3460^2 .

It is a cyclic number.

It is not a de Polignac number, because 18266681 - 2¹⁸ = 18004537 is a prime.

It is a super-2 number, since 2×18266681² = 667343269511522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18266671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1031 + ... + 6131.

It is an arithmetic number, because the mean of its divisors is an integer number (4568841).

Almost surely, 2^18266681 is an apocalyptic number.

It is an amenable number.

18266681 is a deficient number, since it is larger than the sum of its proper divisors (8683).

18266681 is an equidigital number, since it uses as much as digits as its factorization.

18266681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8682.

The product of its digits is 27648, while the sum is 38.

The square root of 18266681 is about 4273.9537901105. The cubic root of 18266681 is about 263.3620625958.

The spelling of 18266681 in words is "eighteen million, two hundred sixty-six thousand, six hundred eighty-one".