18664238 has 4 divisors (see below), whose sum is σ = 27996360. Its totient is φ = 9332118.

The previous prime is 18664229. The next prime is 18664253. The reversal of 18664238 is 83246681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83246681 = 7 ⋅11892383.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4666058 + ... + 4666061.

It is an arithmetic number, because the mean of its divisors is an integer number (6999090).

Almost surely, 2^18664238 is an apocalyptic number.

18664238 is a deficient number, since it is larger than the sum of its proper divisors (9332122).

18664238 is an equidigital number, since it uses as much as digits as its factorization.

18664238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9332121.

The product of its digits is 55296, while the sum is 38.

The square root of 18664238 is about 4320.2127262439. The cubic root of 18664238 is about 265.2589754993.

The spelling of 18664238 in words is "eighteen million, six hundred sixty-four thousand, two hundred thirty-eight".