991303840 has 96 divisors (see below), whose sum is σ = 2399362560. Its totient is φ = 386909184.

The previous prime is 991303801. The next prime is 991303867. The reversal of 991303840 is 48303199.

It is a self number, because there is not a number n which added to its sum of digits gives 991303840.

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, 1632817 + ... + 1633423.

It is an arithmetic number, because the mean of its divisors is an integer number (24993360).

Almost surely, 2^991303840 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 991303840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1199681280).

991303840 is an abundant number, since it is smaller than the sum of its proper divisors (1408058720).

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

991303840 is a wasteful number, since it uses less digits than its factorization.

991303840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854 (or 846 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 991303840 is about 31484.9780053917. The cubic root of 991303840 is about 997.0928365910.

The spelling of 991303840 in words is "nine hundred ninety-one million, three hundred three thousand, eight hundred forty".