18865440 has 192 divisors, whose sum is σ = 72213120. Its totient is φ = 4561920.

The previous prime is 18865387. The next prime is 18865447. The reversal of 18865440 is 4456881.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18865395 and 18865404.

It is not an unprimeable number, because it can be changed into a prime (18865447) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 47322 + ... + 47718.

It is an arithmetic number, because the mean of its divisors is an integer number (376110).

Almost surely, 2^18865440 is an apocalyptic number.

18865440 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 18865440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36106560).

18865440 is an abundant number, since it is smaller than the sum of its proper divisors (53347680).

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

18865440 is a wasteful number, since it uses less digits than its factorization.

18865440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 18865440 is about 4343.4364275306. The cubic root of 18865440 is about 266.2087418712.

The spelling of 18865440 in words is "eighteen million, eight hundred sixty-five thousand, four hundred forty".