18121584 has 80 divisors (see below), whose sum is σ = 51059232. Its totient is φ = 5505024.

The previous prime is 18121583. The next prime is 18121589. The reversal of 18121584 is 48512181.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70384 + ... + 70640.

Almost surely, 2^18121584 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 18121584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25529616).

18121584 is an abundant number, since it is smaller than the sum of its proper divisors (32937648).

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

18121584 is a wasteful number, since it uses less digits than its factorization.

18121584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 388 counting only the distinct ones).

The product of its digits is 2560, while the sum is 30.

The square root of 18121584 is about 4256.9453837229. The cubic root of 18121584 is about 262.6628902833.

The spelling of 18121584 in words is "eighteen million, one hundred twenty-one thousand, five hundred eighty-four".