18238818 has 24 divisors (see below), whose sum is σ = 39501648. Its totient is φ = 5611632.

The previous prime is 18238811. The next prime is 18238849. The reversal of 18238818 is 81883281.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (18238811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7980 + ... + 10007.

It is an arithmetic number, because the mean of its divisors is an integer number (1645902).

Almost surely, 2^18238818 is an apocalyptic number.

18238818 is an abundant number, since it is smaller than the sum of its proper divisors (21262830).

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

18238818 is a wasteful number, since it uses less digits than its factorization.

18238818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18018 (or 18005 counting only the distinct ones).

The product of its digits is 24576, while the sum is 39.

The square root of 18238818 is about 4270.6929180169. The cubic root of 18238818 is about 263.2280884064.

The spelling of 18238818 in words is "eighteen million, two hundred thirty-eight thousand, eight hundred eighteen".