18668890 has 32 divisors (see below), whose sum is σ = 35827920. Its totient is φ = 6979584.

The previous prime is 18668861. The next prime is 18668921. The reversal of 18668890 is 9886681.

It can be written as a sum of positive squares in 8 ways, for example, as 4986289 + 13682601 = 2233^2 + 3699^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18668890.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32526 + ... + 33094.

Almost surely, 2^18668890 is an apocalyptic number.

18668890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18668890 is a deficient number, since it is larger than the sum of its proper divisors (17159030).

18668890 is a wasteful number, since it uses less digits than its factorization.

18668890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786.

The product of its (nonzero) digits is 165888, while the sum is 46.

The square root of 18668890 is about 4320.7510921135. The cubic root of 18668890 is about 265.2810119780.

The spelling of 18668890 in words is "eighteen million, six hundred sixty-eight thousand, eight hundred ninety".