18686868 has 12 divisors (see below), whose sum is σ = 43602720. Its totient is φ = 6228952.

The previous prime is 18686849. The next prime is 18686873. The reversal of 18686868 is 86868681.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 18686868.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778608 + ... + 778631.

It is an arithmetic number, because the mean of its divisors is an integer number (3633560).

Almost surely, 2^18686868 is an apocalyptic number.

It is an amenable number.

18686868 is an abundant number, since it is smaller than the sum of its proper divisors (24915852).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18686868 is a wasteful number, since it uses less digits than its factorization.

18686868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1557246 (or 1557244 counting only the distinct ones).

The product of its digits is 884736, while the sum is 51.

The square root of 18686868 is about 4322.8310168222. The cubic root of 18686868 is about 265.3661391949.

The spelling of 18686868 in words is "eighteen million, six hundred eighty-six thousand, eight hundred sixty-eight".