18181899 has 12 divisors (see below), whose sum is σ = 26559000. Its totient is φ = 11984544.

The previous prime is 18181873. The next prime is 18181907. The reversal of 18181899 is 99818181.

It is not a de Polignac number, because 18181899 - 2⁸ = 18181643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18181829) 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, 10549 + ... + 12150.

It is an arithmetic number, because the mean of its divisors is an integer number (2213250).

Almost surely, 2^18181899 is an apocalyptic number.

18181899 is a deficient number, since it is larger than the sum of its proper divisors (8377101).

18181899 is a wasteful number, since it uses less digits than its factorization.

18181899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22794 (or 22791 counting only the distinct ones).

The product of its digits is 41472, while the sum is 45.

The square root of 18181899 is about 4264.0238038735. The cubic root of 18181899 is about 262.9539790419.

The spelling of 18181899 in words is "eighteen million, one hundred eighty-one thousand, eight hundred ninety-nine".