18990899 has 4 divisors (see below), whose sum is σ = 19990440. Its totient is φ = 17991360.

The previous prime is 18990883. The next prime is 18990901. The reversal of 18990899 is 99809981.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18990899 - 2⁴ = 18990883 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18990899.

It is not an unprimeable number, because it can be changed into a prime (18990809) 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, 499742 + ... + 499779.

It is an arithmetic number, because the mean of its divisors is an integer number (4997610).

Almost surely, 2^18990899 is an apocalyptic number.

18990899 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

18990899 is a deficient number, since it is larger than the sum of its proper divisors (999541).

18990899 is an equidigital number, since it uses as much as digits as its factorization.

18990899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999540.

The product of its (nonzero) digits is 419904, while the sum is 53.

The square root of 18990899 is about 4357.8548622000. The cubic root of 18990899 is about 266.7975525881.

The spelling of 18990899 in words is "eighteen million, nine hundred ninety thousand, eight hundred ninety-nine".