18000440 has 16 divisors (see below), whose sum is σ = 40501080. Its totient is φ = 7200160.

The previous prime is 18000439. The next prime is 18000457. The reversal of 18000440 is 4400081.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224966 + ... + 225045.

Almost surely, 2^18000440 is an apocalyptic number.

18000440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18000440 is an abundant number, since it is smaller than the sum of its proper divisors (22500640).

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

18000440 is a wasteful number, since it uses less digits than its factorization.

18000440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450022 (or 450018 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 18000440 is about 4242.6925412997. The cubic root of 18000440 is about 262.0762748224.

The spelling of 18000440 in words is "eighteen million, four hundred forty", and thus it is an aban number.