18991506688 has 144 divisors (see below), whose sum is σ = 48789135360. Its totient is φ = 7160371200.

The previous prime is 18991506679. The next prime is 18991506707. The reversal of 18991506688 is 88660519981.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 595533 + ... + 626611.

It is an arithmetic number, because the mean of its divisors is an integer number (338813440).

Almost surely, 2^18991506688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18991506688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24394567680).

18991506688 is an abundant number, since it is smaller than the sum of its proper divisors (29797628672).

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

18991506688 is a wasteful number, since it uses less digits than its factorization.

18991506688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31144 (or 31130 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 61.

The spelling of 18991506688 in words is "eighteen billion, nine hundred ninety-one million, five hundred six thousand, six hundred eighty-eight".