18091899 has 12 divisors (see below), whose sum is σ = 29866096. Its totient is φ = 10338192.

The previous prime is 18091891. The next prime is 18091919. The reversal of 18091899 is 99819081.

It is not a de Polignac number, because 18091899 - 2³ = 18091891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18091891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 143524 + ... + 143649.

Almost surely, 2^18091899 is an apocalyptic number.

18091899 is a deficient number, since it is larger than the sum of its proper divisors (11774197).

18091899 is a wasteful number, since it uses less digits than its factorization.

18091899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287186 (or 287183 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 18091899 is about 4253.4572996564. The cubic root of 18091899 is about 262.5193890440.

The spelling of 18091899 in words is "eighteen million, ninety-one thousand, eight hundred ninety-nine".