991108872 has 160 divisors (see below), whose sum is σ = 3093413400. Its totient is φ = 294368256.

The previous prime is 991108871. The next prime is 991108873. The reversal of 991108872 is 278801199.

It is an interprime number because it is at equal distance from previous prime (991108871) and next prime (991108873).

It can be written as a sum of positive squares in 4 ways, for example, as 702992196 + 288116676 = 26514^2 + 16974^2 .

It is a super-2 number, since 2×991108872² = 1964593592314224768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (991108871) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 242268 + ... + 246324.

Almost surely, 2^991108872 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 991108872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1546706700).

991108872 is an abundant number, since it is smaller than the sum of its proper divisors (2102304528).

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

991108872 is a wasteful number, since it uses less digits than its factorization.

991108872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4117 (or 4104 counting only the distinct ones).

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

The square root of 991108872 is about 31481.8816464328. The cubic root of 991108872 is about 997.0274634482.

The spelling of 991108872 in words is "nine hundred ninety-one million, one hundred eight thousand, eight hundred seventy-two".