18185816 has 24 divisors (see below), whose sum is σ = 37482060. Its totient is φ = 8265840.

The previous prime is 18185803. The next prime is 18185819. The reversal of 18185816 is 61858181.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 18185816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18185819) 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 5 ways as a sum of consecutive naturals, for example, 8426 + ... + 10361.

Almost surely, 2^18185816 is an apocalyptic number.

It is an amenable number.

18185816 is an abundant number, since it is smaller than the sum of its proper divisors (19296244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18185816 is a wasteful number, since it uses less digits than its factorization.

18185816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18815 (or 18800 counting only the distinct ones).

The product of its digits is 15360, while the sum is 38.

The square root of 18185816 is about 4264.4830870810. The cubic root of 18185816 is about 262.9728607656.

The spelling of 18185816 in words is "eighteen million, one hundred eighty-five thousand, eight hundred sixteen".