991306320 has 80 divisors (see below), whose sum is σ = 3076440000. Its totient is φ = 264056832.

The previous prime is 991306289. The next prime is 991306343. The reversal of 991306320 is 23603199.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 298107 + ... + 301413.

It is an arithmetic number, because the mean of its divisors is an integer number (38455500).

Almost surely, 2^991306320 is an apocalyptic number.

It is an amenable number.

991306320 is an abundant number, since it is smaller than the sum of its proper divisors (2085133680).

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

991306320 is a wasteful number, since it uses less digits than its factorization.

991306320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4572 (or 4566 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 991306320 is about 31485.0173892282. The cubic root of 991306320 is about 997.0936680845.

The spelling of 991306320 in words is "nine hundred ninety-one million, three hundred six thousand, three hundred twenty".