18681864 has 64 divisors (see below), whose sum is σ = 50155200. Its totient is φ = 5780736.

The previous prime is 18681863. The next prime is 18681899. The reversal of 18681864 is 46818681.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (18681863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23782 + ... + 24554.

It is an arithmetic number, because the mean of its divisors is an integer number (783675).

Almost surely, 2^18681864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18681864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25077600).

18681864 is an abundant number, since it is smaller than the sum of its proper divisors (31473336).

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

18681864 is a wasteful number, since it uses less digits than its factorization.

18681864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854 (or 850 counting only the distinct ones).

The product of its digits is 73728, while the sum is 42.

The square root of 18681864 is about 4322.2521906987. The cubic root of 18681864 is about 265.3424503544.

The spelling of 18681864 in words is "eighteen million, six hundred eighty-one thousand, eight hundred sixty-four".