991887120 has 480 divisors, whose sum is σ = 4075239168. Its totient is φ = 219469824.

The previous prime is 991887119. The next prime is 991887133. The reversal of 991887120 is 21788199.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5034862 + ... + 5035058.

Almost surely, 2^991887120 is an apocalyptic number.

991887120 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991887120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2037619584).

991887120 is an abundant number, since it is smaller than the sum of its proper divisors (3083352048).

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

991887120 is a wasteful number, since it uses less digits than its factorization.

991887120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 45.

The square root of 991887120 is about 31494.2394732751. The cubic root of 991887120 is about 997.2883603231.

The spelling of 991887120 in words is "nine hundred ninety-one million, eight hundred eighty-seven thousand, one hundred twenty".