18443556 has 18 divisors (see below), whose sum is σ = 46621302. Its totient is φ = 6147840.

The previous prime is 18443549. The next prime is 18443561. The reversal of 18443556 is 65534481.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 10692900 + 7750656 = 3270^2 + 2784^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 512321 = 18443556 / (1 + 8 + 4 + 4 + 3 + 5 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 18443556.

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 5 ways as a sum of consecutive naturals, for example, 256125 + ... + 256196.

Almost surely, 2^18443556 is an apocalyptic number.

It is an amenable number.

18443556 is an abundant number, since it is smaller than the sum of its proper divisors (28177746).

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

18443556 is a wasteful number, since it uses less digits than its factorization.

18443556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512331 (or 512326 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 18443556 is about 4294.5961393360. The cubic root of 18443556 is about 264.2093724750.

The spelling of 18443556 in words is "eighteen million, four hundred forty-three thousand, five hundred fifty-six".