16561416561 has 16 divisors (see below), whose sum is σ = 22695120000. Its totient is φ = 10734761088.

The previous prime is 16561416527. The next prime is 16561416563.

16561416561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 16561416561 - 2¹⁵ = 16561383793 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16561416563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101965 + ... + 208613.

It is an arithmetic number, because the mean of its divisors is an integer number (1418445000).

Almost surely, 2^16561416561 is an apocalyptic number.

It is an amenable number.

16561416561 is a deficient number, since it is larger than the sum of its proper divisors (6133703439).

16561416561 is a wasteful number, since it uses less digits than its factorization.

16561416561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108088.

The product of its digits is 129600, while the sum is 42.

The spelling of 16561416561 in words is "sixteen billion, five hundred sixty-one million, four hundred sixteen thousand, five hundred sixty-one".