991841280 has 176 divisors, whose sum is σ = 3276248064. Its totient is φ = 255836160.

The previous prime is 991841243. The next prime is 991841303. The reversal of 991841280 is 82148199.

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, 475119 + ... + 477201.

Almost surely, 2^991841280 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 991841280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1638124032).

991841280 is an abundant number, since it is smaller than the sum of its proper divisors (2284406784).

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

991841280 is a wasteful number, since it uses less digits than its factorization.

991841280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2142 (or 2124 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 42.

The square root of 991841280 is about 31493.5117127322. The cubic root of 991841280 is about 997.2729968805.

The spelling of 991841280 in words is "nine hundred ninety-one million, eight hundred forty-one thousand, two hundred eighty".