18664678 has 4 divisors (see below), whose sum is σ = 27997020. Its totient is φ = 9332338.

The previous prime is 18664673. The next prime is 18664703. The reversal of 18664678 is 87646681.

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: 87646681 = 47 ⋅1864823.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18664673) 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 as a sum of consecutive naturals, namely, 4666168 + ... + 4666171.

It is an arithmetic number, because the mean of its divisors is an integer number (6999255).

Almost surely, 2^18664678 is an apocalyptic number.

18664678 is a deficient number, since it is larger than the sum of its proper divisors (9332342).

18664678 is an equidigital number, since it uses as much as digits as its factorization.

18664678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9332341.

The product of its digits is 387072, while the sum is 46.

The square root of 18664678 is about 4320.2636493622. The cubic root of 18664678 is about 265.2610599318.

The spelling of 18664678 in words is "eighteen million, six hundred sixty-four thousand, six hundred seventy-eight".