991137056 has 96 divisors (see below), whose sum is σ = 2466777600. Its totient is φ = 381459456.

The previous prime is 991137029. The next prime is 991137073. The reversal of 991137056 is 650731199.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103145 + ... + 112343.

It is an arithmetic number, because the mean of its divisors is an integer number (25695600).

Almost surely, 2^991137056 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 991137056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1233388800).

991137056 is an abundant number, since it is smaller than the sum of its proper divisors (1475640544).

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

991137056 is a wasteful number, since it uses less digits than its factorization.

991137056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9266 (or 9258 counting only the distinct ones).

The product of its (nonzero) digits is 51030, while the sum is 41.

The square root of 991137056 is about 31482.3292657961. The cubic root of 991137056 is about 997.0369141273.

The spelling of 991137056 in words is "nine hundred ninety-one million, one hundred thirty-seven thousand, fifty-six".