16561016511065 has 32 divisors (see below), whose sum is σ = 21516196042656. Its totient is φ = 12164398202880.

The previous prime is 16561016510999. The next prime is 16561016511071. The reversal of 16561016511065 is 56011561016561.

It can be written as a sum of positive squares in 16 ways, for example, as 5755253778121 + 10805762732944 = 2399011^2 + 3287212^2 .

It is not a de Polignac number, because 16561016511065 - 2¹⁸ = 16561016248921 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82458347 + ... + 82658943.

It is an arithmetic number, because the mean of its divisors is an integer number (672381126333).

Almost surely, 2^{16561016511065} is an apocalyptic number.

It is an amenable number.

16561016511065 is a deficient number, since it is larger than the sum of its proper divisors (4955179531591).

16561016511065 is a wasteful number, since it uses less digits than its factorization.

16561016511065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207389.

The product of its (nonzero) digits is 162000, while the sum is 44.

The spelling of 16561016511065 in words is "sixteen trillion, five hundred sixty-one billion, sixteen million, five hundred eleven thousand, sixty-five".