991043502280 has 128 divisors (see below), whose sum is σ = 2436470668800. Its totient is φ = 360598182912.

The previous prime is 991043502271. The next prime is 991043502311. The reversal of 991043502280 is 82205340199.

It is a super-2 number, since 2×991043502280² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17105601 + ... + 17163439.

It is an arithmetic number, because the mean of its divisors is an integer number (19034927100).

Almost surely, 2^991043502280 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 991043502280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1218235334400).

991043502280 is an abundant number, since it is smaller than the sum of its proper divisors (1445427166520).

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

991043502280 is a wasteful number, since it uses less digits than its factorization.

991043502280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58343 (or 58339 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The spelling of 991043502280 in words is "nine hundred ninety-one billion, forty-three million, five hundred two thousand, two hundred eighty".