18868821 has 16 divisors (see below), whose sum is σ = 26391360. Its totient is φ = 11975040.

The previous prime is 18868813. The next prime is 18868831. The reversal of 18868821 is 12886881.

It is not a de Polignac number, because 18868821 - 2³ = 18868813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18868831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4866 + ... + 7836.

It is an arithmetic number, because the mean of its divisors is an integer number (1649460).

Almost surely, 2^18868821 is an apocalyptic number.

It is an amenable number.

18868821 is a deficient number, since it is larger than the sum of its proper divisors (7522539).

18868821 is a wasteful number, since it uses less digits than its factorization.

18868821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3076.

The product of its digits is 49152, while the sum is 42.

The square root of 18868821 is about 4343.8256180468. The cubic root of 18868821 is about 266.2246439297.

The spelling of 18868821 in words is "eighteen million, eight hundred sixty-eight thousand, eight hundred twenty-one".