16561688704 has 128 divisors (see below), whose sum is σ = 36683280000. Its totient is φ = 7384965120.

The previous prime is 16561688699. The next prime is 16561688771. The reversal of 16561688704 is 40788616561.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27648597 + ... + 27649195.

It is an arithmetic number, because the mean of its divisors is an integer number (286588125).

Almost surely, 2^16561688704 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16561688704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18341640000).

16561688704 is an abundant number, since it is smaller than the sum of its proper divisors (20121591296).

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

16561688704 is a wasteful number, since it uses less digits than its factorization.

16561688704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 966 (or 954 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 52.

The spelling of 16561688704 in words is "sixteen billion, five hundred sixty-one million, six hundred eighty-eight thousand, seven hundred four".