18044388 has 18 divisors (see below), whose sum is σ = 45612294. Its totient is φ = 6014784.

The previous prime is 18044353. The next prime is 18044399. The reversal of 18044388 is 88344081.

It can be written as a sum of positive squares in only one way, i.e., 17040384 + 1004004 = 4128^2 + 1002^2 .

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: 501233 = 18044388 / (1 + 8 + 0 + 4 + 4 + 3 + 8 + 8).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 250581 + ... + 250652.

Almost surely, 2^18044388 is an apocalyptic number.

18044388 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18044388 is an abundant number, since it is smaller than the sum of its proper divisors (27567906).

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

18044388 is a wasteful number, since it uses less digits than its factorization.

18044388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501243 (or 501238 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 18044388 is about 4247.8686420369. The cubic root of 18044388 is about 262.2893875264.

The spelling of 18044388 in words is "eighteen million, forty-four thousand, three hundred eighty-eight".