15991280928 has 432 divisors, whose sum is σ = 57679503840. Its totient is φ = 4296886272.

The previous prime is 15991280927. The next prime is 15991280947. The reversal of 15991280928 is 82908219951.

15991280928 is a `hidden beast` number, since 1 + 599 + 1 + 28 + 0 + 9 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (15991280927) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 12234451 + ... + 12235757.

It is an arithmetic number, because the mean of its divisors is an integer number (133517370).

Almost surely, 2^15991280928 is an apocalyptic number.

15991280928 is a gapful number since it is divisible by the number (18) 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 15991280928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28839751920).

15991280928 is an abundant number, since it is smaller than the sum of its proper divisors (41688222912).

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

15991280928 is a wasteful number, since it uses less digits than its factorization.

15991280928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1374 (or 1336 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 54.

The spelling of 15991280928 in words is "fifteen billion, nine hundred ninety-one million, two hundred eighty thousand, nine hundred twenty-eight".