15661971072 has 768 divisors, whose sum is σ = 56710368000. Its totient is φ = 4087480320.

The previous prime is 15661971047. The next prime is 15661971107. The reversal of 15661971072 is 27017916651.

15661971072 is a `hidden beast` number, since 1 + 566 + 1 + 9 + 7 + 10 + 72 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 143687754 + ... + 143687862.

It is an arithmetic number, because the mean of its divisors is an integer number (73841625).

Almost surely, 2^15661971072 is an apocalyptic number.

15661971072 is a gapful number since it is divisible by the number (12) 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 15661971072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28355184000).

15661971072 is an abundant number, since it is smaller than the sum of its proper divisors (41048396928).

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

15661971072 is a wasteful number, since it uses less digits than its factorization.

15661971072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 158760, while the sum is 45.

The spelling of 15661971072 in words is "fifteen billion, six hundred sixty-one million, nine hundred seventy-one thousand, seventy-two".