991323168 has 96 divisors (see below), whose sum is σ = 2849878080. Its totient is φ = 299228160.

The previous prime is 991323167. The next prime is 991323173. The reversal of 991323168 is 861323199.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (991323163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 290818 + ... + 294206.

It is an arithmetic number, because the mean of its divisors is an integer number (29686230).

Almost surely, 2^991323168 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 991323168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1424939040).

991323168 is an abundant number, since it is smaller than the sum of its proper divisors (1858554912).

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

991323168 is a wasteful number, since it uses less digits than its factorization.

991323168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3690 (or 3682 counting only the distinct ones).

The product of its digits is 69984, while the sum is 42.

The square root of 991323168 is about 31485.2849439226. The cubic root of 991323168 is about 997.0993168393.

The spelling of 991323168 in words is "nine hundred ninety-one million, three hundred twenty-three thousand, one hundred sixty-eight".