18561681680 has 40 divisors (see below), whose sum is σ = 43175319192. Its totient is φ = 7421333504.

The previous prime is 18561681679. The next prime is 18561681689. The reversal of 18561681680 is 8618616581.

It can be written as a sum of positive squares in 4 ways, for example, as 8676549904 + 9885131776 = 93148^2 + 99424^2 .

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

It is not an unprimeable number, because it can be changed into a prime (18561681689) 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 7 ways as a sum of consecutive naturals, for example, 130802 + ... + 232878.

Almost surely, 2^18561681680 is an apocalyptic number.

18561681680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18561681680 is an abundant number, since it is smaller than the sum of its proper divisors (24613637512).

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

18561681680 is a wasteful number, since it uses less digits than its factorization.

18561681680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104363 (or 104357 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 50.

The spelling of 18561681680 in words is "eighteen billion, five hundred sixty-one million, six hundred eighty-one thousand, six hundred eighty".