8991728640 has 264 divisors, whose sum is σ = 31544892288. Its totient is φ = 2367897600.

The previous prime is 8991728633. The next prime is 8991728657. The reversal of 8991728640 is 468271998.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3823465 + ... + 3825815.

Almost surely, 2^8991728640 is an apocalyptic number.

8991728640 is a gapful number since it is divisible by the number (80) 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 8991728640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15772446144).

8991728640 is an abundant number, since it is smaller than the sum of its proper divisors (22553163648).

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

8991728640 is a wasteful number, since it uses less digits than its factorization.

8991728640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2465 (or 2444 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The square root of 8991728640 is about 94824.7258894008. The cubic root of 8991728640 is about 2079.4464009943.

The spelling of 8991728640 in words is "eight billion, nine hundred ninety-one million, seven hundred twenty-eight thousand, six hundred forty".