18665440 has 48 divisors (see below), whose sum is σ = 45139248. Its totient is φ = 7289856.

The previous prime is 18665431. The next prime is 18665459. The reversal of 18665440 is 4456681.

It is a junction number, because it is equal to n+sod(n) for n = 18665396 and 18665405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5524 + ... + 8236.

It is an arithmetic number, because the mean of its divisors is an integer number (940401).

Almost surely, 2^18665440 is an apocalyptic number.

18665440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18665440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22569624).

18665440 is an abundant number, since it is smaller than the sum of its proper divisors (26473808).

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

18665440 is a wasteful number, since it uses less digits than its factorization.

18665440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2771 (or 2763 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 18665440 is about 4320.3518375243. The cubic root of 18665440 is about 265.2646697124.

The spelling of 18665440 in words is "eighteen million, six hundred sixty-five thousand, four hundred forty".