999128880 has 240 divisors, whose sum is σ = 3510936000. Its totient is φ = 254306304.

The previous prime is 999128873. The next prime is 999128903. The reversal of 999128880 is 88821999.

It is a happy number.

It is a Cunningham number, because it is equal to 31609²-1.

It is a tau number, because it is divible by the number of its divisors (240).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2275701 + ... + 2276139.

It is an arithmetic number, because the mean of its divisors is an integer number (14628900).

Almost surely, 2^999128880 is an apocalyptic number.

999128880 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 999128880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1755468000).

999128880 is an abundant number, since it is smaller than the sum of its proper divisors (2511807120).

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

999128880 is a wasteful number, since it uses less digits than its factorization.

999128880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596 (or 587 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 54.

The square root of 999128880 is about 31608.9999841817. Note that the first 4 decimals coincide. The cubic root of 999128880 is about 999.7095423092.

The spelling of 999128880 in words is "nine hundred ninety-nine million, one hundred twenty-eight thousand, eight hundred eighty".