991127766916 has 243 divisors, whose sum is σ = 2214774741711. Its totient is φ = 386880248832.

The previous prime is 991127766913. The next prime is 991127766929. The reversal of 991127766916 is 619667721199.

The square root of 991127766916 is 995554.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 1309716100 + 989818050816 = 36190^2 + 994896^2 .

Its product of digits (15431472) is a multiple of the sum of its prime divisors (162).

It is not an unprimeable number, because it can be changed into a prime (991127766911) 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 80 ways as a sum of consecutive naturals, for example, 11136267000 + ... + 11136267088.

Almost surely, 2^991127766916 is an apocalyptic number.

991127766916 is the 995554-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991127766916

991127766916 is an abundant number, since it is smaller than the sum of its proper divisors (1223646974795).

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

991127766916 is a wasteful number, since it uses less digits than its factorization.

991127766916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 162 counting only the distinct ones).

The product of its digits is 15431472, while the sum is 64.

Multiplying 991127766916 by its sum of digits (64), we get a square (63432177082624 = 7964432²).

The spelling of 991127766916 in words is "nine hundred ninety-one billion, one hundred twenty-seven million, seven hundred sixty-six thousand, nine hundred sixteen".