18640044 has 72 divisors (see below), whose sum is σ = 49573888. Its totient is φ = 6123600.

The previous prime is 18640043. The next prime is 18640067. The reversal of 18640044 is 44004681.

18640044 is a `hidden beast` number, since 18 + 640 + 0 + 4 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (18640043) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123369 + ... + 123519.

Almost surely, 2^18640044 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 18640044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24786944).

18640044 is an abundant number, since it is smaller than the sum of its proper divisors (30933844).

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

18640044 is a wasteful number, since it uses less digits than its factorization.

18640044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 18640044 is about 4317.4117246332. The cubic root of 18640044 is about 265.1443096755.

The spelling of 18640044 in words is "eighteen million, six hundred forty thousand, forty-four".