18115440 has 160 divisors (see below), whose sum is σ = 65995776. Its totient is φ = 4024320.

The previous prime is 18115403. The next prime is 18115441. The reversal of 18115440 is 4451181.

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 18115440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18115441) 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 31 ways as a sum of consecutive naturals, for example, 68749 + ... + 69011.

Almost surely, 2^18115440 is an apocalyptic number.

18115440 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 18115440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32997888).

18115440 is an abundant number, since it is smaller than the sum of its proper divisors (47880336).

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

18115440 is a wasteful number, since it uses less digits than its factorization.

18115440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 18115440 is about 4256.2236783327. The cubic root of 18115440 is about 262.6332022381.

The spelling of 18115440 in words is "eighteen million, one hundred fifteen thousand, four hundred forty".