18549081 has 20 divisors (see below), whose sum is σ = 28097652. Its totient is φ = 12192768.

The previous prime is 18549071. The next prime is 18549101. The reversal of 18549081 is 18094581.

It can be written as a sum of positive squares in 2 ways, for example, as 16040025 + 2509056 = 4005^2 + 1584^2 .

It is not a de Polignac number, because 18549081 - 2¹⁹ = 18024793 is a prime.

It is a super-2 number, since 2×18549081² = 688136811889122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (18549071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4345 + ... + 7481.

Almost surely, 2^18549081 is an apocalyptic number.

It is an amenable number.

18549081 is a deficient number, since it is larger than the sum of its proper divisors (9548571).

18549081 is an equidigital number, since it uses as much as digits as its factorization.

18549081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3222 (or 3213 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 18549081 is about 4306.8644046452. The cubic root of 18549081 is about 264.7123067460.

The spelling of 18549081 in words is "eighteen million, five hundred forty-nine thousand, eighty-one".