991456128000 has 1056 divisors, whose sum is σ = 3877661249280. Its totient is φ = 242152243200.

The previous prime is 991456127993. The next prime is 991456128001. The reversal of 991456128000 is 821654199.

991456128000 is a `hidden beast` number, since 9 + 9 + 1 + 4 + 561 + 2 + 80 + 0 + 0 = 666.

991456128000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not an unprimeable number, because it can be changed into a prime (991456128001) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3579263862 + ... + 3579264138.

Almost surely, 2^991456128000 is an apocalyptic number.

991456128000 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 991456128000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1938830624640).

991456128000 is an abundant number, since it is smaller than the sum of its proper divisors (2886205121280).

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

991456128000 is a wasteful number, since it uses less digits than its factorization.

991456128000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 991456128000 in words is "nine hundred ninety-one billion, four hundred fifty-six million, one hundred twenty-eight thousand".