18003840 has 64 divisors (see below), whose sum is σ = 57393360. Its totient is φ = 4800512.

The previous prime is 18003827. The next prime is 18003841. The reversal of 18003840 is 4830081.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 18003840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18003841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2769 + ... + 6608.

Almost surely, 2^18003840 is an apocalyptic number.

18003840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18003840 is an abundant number, since it is smaller than the sum of its proper divisors (39389520).

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

18003840 is an equidigital number, since it uses as much as digits as its factorization.

18003840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9399 (or 9387 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 18003840 is about 4243.0932113259. The cubic root of 18003840 is about 262.0927744790.

The spelling of 18003840 in words is "eighteen million, three thousand, eight hundred forty".