991807488 has 144 divisors (see below), whose sum is σ = 3274165440. Its totient is φ = 283336704.

The previous prime is 991807469. The next prime is 991807493. The reversal of 991807488 is 884708199.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 125181 + ... + 132867.

It is an arithmetic number, because the mean of its divisors is an integer number (22737260).

Almost surely, 2^991807488 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 991807488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1637082720).

991807488 is an abundant number, since it is smaller than the sum of its proper divisors (2282357952).

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

991807488 is a wasteful number, since it uses less digits than its factorization.

991807488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7722 (or 7699 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 54.

The square root of 991807488 is about 31492.9752167051. The cubic root of 991807488 is about 997.2616710657.

The spelling of 991807488 in words is "nine hundred ninety-one million, eight hundred seven thousand, four hundred eighty-eight".