15991820928 has 80 divisors (see below), whose sum is σ = 47591430810. Its totient is φ = 5330603520.

The previous prime is 15991820881. The next prime is 15991820947. The reversal of 15991820928 is 82902819951.

15991820928 is a `hidden beast` number, since 1 + 599 + 1 + 8 + 20 + 9 + 28 = 666.

15991820928 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 14648745024 + 1343075904 = 121032^2 + 36648^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 760843 + ... + 781578.

Almost surely, 2^15991820928 is an apocalyptic number.

15991820928 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

15991820928 is an abundant number, since it is smaller than the sum of its proper divisors (31599609882).

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

15991820928 is an equidigital number, since it uses as much as digits as its factorization.

15991820928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542447 (or 1542426 counting only the distinct ones).

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

The spelling of 15991820928 in words is "fifteen billion, nine hundred ninety-one million, eight hundred twenty thousand, nine hundred twenty-eight".