18001840 has 20 divisors (see below), whose sum is σ = 41854464. Its totient is φ = 7200704.

The previous prime is 18001817. The next prime is 18001843. The reversal of 18001840 is 4810081.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (18001843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112432 + ... + 112591.

Almost surely, 2^18001840 is an apocalyptic number.

18001840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18001840 is an abundant number, since it is smaller than the sum of its proper divisors (23852624).

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

18001840 is a wasteful number, since it uses less digits than its factorization.

18001840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225036 (or 225030 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 18001840 is about 4242.8575276575. The cubic root of 18001840 is about 262.0830690503.

The spelling of 18001840 in words is "eighteen million, one thousand, eight hundred forty".