16561661521118 has 16 divisors (see below), whose sum is σ = 28538525556960. Its totient is φ = 7061078486016.

The previous prime is 16561661520949. The next prime is 16561661521151. The reversal of 16561661521118 is 81112516616561.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3064701503 + ... + 3064706906.

It is an arithmetic number, because the mean of its divisors is an integer number (1783657847310).

Almost surely, 2^{16561661521118} is an apocalyptic number.

16561661521118 is a deficient number, since it is larger than the sum of its proper divisors (11976864035842).

16561661521118 is a wasteful number, since it uses less digits than its factorization.

16561661521118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6129408611.

The product of its digits is 518400, while the sum is 50.

The spelling of 16561661521118 in words is "sixteen trillion, five hundred sixty-one billion, six hundred sixty-one million, five hundred twenty-one thousand, one hundred eighteen".