16556064320721 has 32 divisors (see below), whose sum is σ = 24287027060736. Its totient is φ = 9986441760000.

The previous prime is 16556064320689. The next prime is 16556064320759. The reversal of 16556064320721 is 12702346065561.

It is not a de Polignac number, because 16556064320721 - 2⁵ = 16556064320689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16556064320771) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34436415 + ... + 34913876.

It is an arithmetic number, because the mean of its divisors is an integer number (758969595648).

Almost surely, 2^{16556064320721} is an apocalyptic number.

It is an amenable number.

16556064320721 is a deficient number, since it is larger than the sum of its proper divisors (7730962740015).

16556064320721 is a wasteful number, since it uses less digits than its factorization.

16556064320721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69350493.

The product of its (nonzero) digits is 1814400, while the sum is 48.

The spelling of 16556064320721 in words is "sixteen trillion, five hundred fifty-six billion, sixty-four million, three hundred twenty thousand, seven hundred twenty-one".