999998566681128 has 64 divisors (see below), whose sum is σ = 2857141125788160. Its totient is φ = 285713639810496.

The previous prime is 999998566681069. The next prime is 999998566681223. The reversal of 999998566681128 is 821186665899999.

It is a happy number.

999998566681128 is a nontrivial binomial coefficient, being equal to C(44721328, 2).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 356373075 + ... + 359168157.

It is an arithmetic number, because the mean of its divisors is an integer number (44642830090440).

Almost surely, 2^{999998566681128} is an apocalyptic number.

999998566681128 is the 44721327-th triangular number and also the 22360664-th hexagonal number.

It is an amenable number.

999998566681128 is an abundant number, since it is smaller than the sum of its proper divisors (1857142559107032).

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

999998566681128 is a wasteful number, since it uses less digits than its factorization.

999998566681128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4924686 (or 4924682 counting only the distinct ones).

The product of its digits is 65303470080, while the sum is 96.

The spelling of 999998566681128 in words is "nine hundred ninety-nine trillion, nine hundred ninety-eight billion, five hundred sixty-six million, six hundred eighty-one thousand, one hundred twenty-eight".