9999966660256 has 48 divisors (see below), whose sum is σ = 20145763671264. Its totient is φ = 4883587801344.

The previous prime is 9999966660251. The next prime is 9999966660259. The reversal of 9999966660256 is 6520666699999.

9999966660256 is a nontrivial binomial coefficient, being equal to C(4472129, 2).

It is a self number, because there is not a number n which added to its sum of digits gives 9999966660256.

It is not an unprimeable number, because it can be changed into a prime (9999966660251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96098751 + ... + 96202753.

It is an arithmetic number, because the mean of its divisors is an integer number (419703409818).

Almost surely, 2^{9999966660256} is an apocalyptic number.

9999966660256 is the 4472128-th triangular number.

9999966660256 is the 1490710-th centered nonagonal number.

It is an amenable number.

9999966660256 is an abundant number, since it is smaller than the sum of its proper divisors (10145797011008).

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

9999966660256 is a wasteful number, since it uses less digits than its factorization.

9999966660256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173933 (or 173925 counting only the distinct ones).

The product of its (nonzero) digits is 4591650240, while the sum is 82.

The spelling of 9999966660256 in words is "nine trillion, nine hundred ninety-nine billion, nine hundred sixty-six million, six hundred sixty thousand, two hundred fifty-six".