18664879 has 2 divisors, whose sum is σ = 18664880. Its totient is φ = 18664878.

The previous prime is 18664873. The next prime is 18664889. The reversal of 18664879 is 97846681.

It is a weak prime.

It is an emirp because it is prime and its reverse (97846681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18664879 - 2⁹ = 18664367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18664873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9332439 + 9332440.

It is an arithmetic number, because the mean of its divisors is an integer number (9332440).

Almost surely, 2^18664879 is an apocalyptic number.

18664879 is a deficient number, since it is larger than the sum of its proper divisors (1).

18664879 is an equidigital number, since it uses as much as digits as its factorization.

18664879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 49.

The square root of 18664879 is about 4320.2869117687. The cubic root of 18664879 is about 265.2620121276.

The spelling of 18664879 in words is "eighteen million, six hundred sixty-four thousand, eight hundred seventy-nine".