18664885 has 4 divisors (see below), whose sum is σ = 22397868. Its totient is φ = 14931904.

The previous prime is 18664879. The next prime is 18664889. The reversal of 18664885 is 58846681.

18664885 = T₃₅₂₆ + T₃₅₂₇ + T₃₅₂₈.

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 5769604 + 12895281 = 2402^2 + 3591^2 .

It is a cyclic number.

It is not a de Polignac number, because 18664885 - 2⁷ = 18664757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18664889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1866484 + ... + 1866493.

It is an arithmetic number, because the mean of its divisors is an integer number (5599467).

Almost surely, 2^18664885 is an apocalyptic number.

18664885 is the 3528-th centered triangular number.

It is an amenable number.

18664885 is a deficient number, since it is larger than the sum of its proper divisors (3732983).

18664885 is an equidigital number, since it uses as much as digits as its factorization.

18664885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3732982.

The product of its digits is 368640, while the sum is 46.

The square root of 18664885 is about 4320.2876061670. The cubic root of 18664885 is about 265.2620405512.

The spelling of 18664885 in words is "eighteen million, six hundred sixty-four thousand, eight hundred eighty-five".