18013840 has 40 divisors (see below), whose sum is σ = 45106488. Its totient is φ = 6650880.

The previous prime is 18013823. The next prime is 18013841. The reversal of 18013840 is 4831081.

It can be written as a sum of positive squares in 4 ways, for example, as 2304 + 18011536 = 48^2 + 4244^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (18013841) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 7621 + ... + 9700.

Almost surely, 2^18013840 is an apocalyptic number.

18013840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18013840 is an abundant number, since it is smaller than the sum of its proper divisors (27092648).

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

18013840 is a wasteful number, since it uses less digits than its factorization.

18013840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17347 (or 17341 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 18013840 is about 4244.2714333558. The cubic root of 18013840 is about 262.1412908445.

The spelling of 18013840 in words is "eighteen million, thirteen thousand, eight hundred forty".