18664609 has 4 divisors (see below), whose sum is σ = 18712980. Its totient is φ = 18616240.

The previous prime is 18664579. The next prime is 18664627. The reversal of 18664609 is 90646681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4579600 + 14085009 = 2140^2 + 3753^2 .

It is a cyclic number.

It is not a de Polignac number, because 18664609 - 2⁵ = 18664577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18664649) 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 3 ways as a sum of consecutive naturals, for example, 23602 + ... + 24379.

It is an arithmetic number, because the mean of its divisors is an integer number (4678245).

Almost surely, 2^18664609 is an apocalyptic number.

It is an amenable number.

18664609 is a deficient number, since it is larger than the sum of its proper divisors (48371).

18664609 is an equidigital number, since it uses as much as digits as its factorization.

18664609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48370.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 18664609 is about 4320.2556637310. The cubic root of 18664609 is about 265.2607330571.

The spelling of 18664609 in words is "eighteen million, six hundred sixty-four thousand, six hundred nine".