18381636 has 144 divisors (see below), whose sum is σ = 59358208. Its totient is φ = 4665600.

The previous prime is 18381613. The next prime is 18381647. The reversal of 18381636 is 63618381.

18381636 is a `hidden beast` number, since 18 + 3 + 8 + 1 + 636 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 18381636.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 101466 + ... + 101646.

Almost surely, 2^18381636 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 18381636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29679104).

18381636 is an abundant number, since it is smaller than the sum of its proper divisors (40976572).

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

18381636 is a wasteful number, since it uses less digits than its factorization.

18381636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242 (or 237 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 18381636 is about 4287.3810187573. The cubic root of 18381636 is about 263.9133668908.

The spelling of 18381636 in words is "eighteen million, three hundred eighty-one thousand, six hundred thirty-six".