18919868 has 24 divisors (see below), whose sum is σ = 36583680. Its totient is φ = 8489520.

The previous prime is 18919843. The next prime is 18919883. The reversal of 18919868 is 86891981.

It is a happy number.

It is a super-2 number, since 2×18919868² = 715922810274848, which contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 755 + ... + 6197.

It is an arithmetic number, because the mean of its divisors is an integer number (1524320).

Almost surely, 2^18919868 is an apocalyptic number.

It is an amenable number.

18919868 is a deficient number, since it is larger than the sum of its proper divisors (17663812).

18919868 is a wasteful number, since it uses less digits than its factorization.

18919868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5537 (or 5535 counting only the distinct ones).

The product of its digits is 248832, while the sum is 50.

The square root of 18919868 is about 4349.6974607437. The cubic root of 18919868 is about 266.4645058077.

The spelling of 18919868 in words is "eighteen million, nine hundred nineteen thousand, eight hundred sixty-eight".