18561440 has 24 divisors (see below), whose sum is σ = 43851780. Its totient is φ = 7424512.

The previous prime is 18561427. The next prime is 18561443. The reversal of 18561440 is 4416581.

It can be written as a sum of positive squares in 2 ways, for example, as 16679056 + 1882384 = 4084^2 + 1372^2 .

It is not an unprimeable number, because it can be changed into a prime (18561443) 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 3 ways as a sum of consecutive naturals, for example, 57845 + ... + 58164.

Almost surely, 2^18561440 is an apocalyptic number.

18561440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18561440 is an abundant number, since it is smaller than the sum of its proper divisors (25290340).

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

18561440 is a wasteful number, since it uses less digits than its factorization.

18561440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116024 (or 116016 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 18561440 is about 4308.2989682704. The cubic root of 18561440 is about 264.7710850950.

The spelling of 18561440 in words is "eighteen million, five hundred sixty-one thousand, four hundred forty".