999994988978128 has 320 divisors, whose sum is σ = 2416615039238400. Its totient is φ = 394514403655680.

The previous prime is 999994988978077. The next prime is 999994988978131. The reversal of 999994988978128 is 821879889499999.

999994988978128 is a nontrivial binomial coefficient, being equal to C(44721248, 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 960986818 + ... + 962026846.

It is an arithmetic number, because the mean of its divisors is an integer number (7551921997620).

Almost surely, 2^{999994988978128} is an apocalyptic number.

999994988978128 is the 44721247-th triangular number and also the 22360624-th hexagonal number.

999994988978128 is the 14907083-rd centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999994988978128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1208307519619200).

999994988978128 is an abundant number, since it is smaller than the sum of its proper divisors (1416620050260272).

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

999994988978128 is a wasteful number, since it uses less digits than its factorization.

999994988978128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040470 (or 1040464 counting only the distinct ones).

The product of its digits is 1097098297344, while the sum is 109.

The spelling of 999994988978128 in words is "nine hundred ninety-nine trillion, nine hundred ninety-four billion, nine hundred eighty-eight million, nine hundred seventy-eight thousand, one hundred twenty-eight".