15991871616 has 192 divisors, whose sum is σ = 53228185920. Its totient is φ = 4513867776.

The previous prime is 15991871603. The next prime is 15991871629. The reversal of 15991871616 is 61617819951.

It is a happy number.

15991871616 is a `hidden beast` number, since 1 + 5 + 9 + 9 + 18 + 7 + 1 + 616 = 666.

It is an interprime number because it is at equal distance from previous prime (15991871603) and next prime (15991871629).

It is a tau number, because it is divible by the number of its divisors (192).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 657366 + ... + 681258.

It is an arithmetic number, because the mean of its divisors is an integer number (277230135).

Almost surely, 2^15991871616 is an apocalyptic number.

15991871616 is a gapful number since it is divisible by the number (16) 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 15991871616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26614092960).

15991871616 is an abundant number, since it is smaller than the sum of its proper divisors (37236314304).

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

15991871616 is a wasteful number, since it uses less digits than its factorization.

15991871616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24003 (or 23988 counting only the distinct ones).

The product of its digits is 816480, while the sum is 54.

The spelling of 15991871616 in words is "fifteen billion, nine hundred ninety-one million, eight hundred seventy-one thousand, six hundred sixteen".