18664873 has 2 divisors, whose sum is σ = 18664874. Its totient is φ = 18664872.

The previous prime is 18664843. The next prime is 18664879. The reversal of 18664873 is 37846681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18045504 + 619369 = 4248^2 + 787^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18664873 is a prime.

It is a super-2 number, since 2×18664873² = 696754968212258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18664879) 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, 9332436 + 9332437.

It is an arithmetic number, because the mean of its divisors is an integer number (9332437).

Almost surely, 2^18664873 is an apocalyptic number.

It is an amenable number.

18664873 is a deficient number, since it is larger than the sum of its proper divisors (1).

18664873 is an equidigital number, since it uses as much as digits as its factorization.

18664873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 43.

The square root of 18664873 is about 4320.2862173703. The cubic root of 18664873 is about 265.2619837039.

The spelling of 18664873 in words is "eighteen million, six hundred sixty-four thousand, eight hundred seventy-three".