991908288 has 112 divisors (see below), whose sum is σ = 3332642560. Its totient is φ = 283398912.

The previous prime is 991908283. The next prime is 991908311. The reversal of 991908288 is 882809199.

It is a happy number.

991908288 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991908283) 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, 28906 + ... + 53097.

Almost surely, 2^991908288 is an apocalyptic number.

It is an amenable number.

991908288 is an abundant number, since it is smaller than the sum of its proper divisors (2340734272).

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

991908288 is a wasteful number, since it uses less digits than its factorization.

991908288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82031 (or 82015 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 54.

The square root of 991908288 is about 31494.5755329390. The cubic root of 991908288 is about 997.2954546956.

The spelling of 991908288 in words is "nine hundred ninety-one million, nine hundred eight thousand, two hundred eighty-eight".