16561625161 has 2 divisors, whose sum is σ = 16561625162. Its totient is φ = 16561625160.

The previous prime is 16561625123. The next prime is 16561625207. The reversal of 16561625161 is 16152616561.

16561625161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13425625161 + 3136000000 = 115869^2 + 56000^2 .

It is a cyclic number.

It is not a de Polignac number, because 16561625161 - 2²¹ = 16559528009 is a prime.

It is not a weakly prime, because it can be changed into another prime (16561625261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8280812580 + 8280812581.

It is an arithmetic number, because the mean of its divisors is an integer number (8280812581).

Almost surely, 2^16561625161 is an apocalyptic number.

It is an amenable number.

16561625161 is a deficient number, since it is larger than the sum of its proper divisors (1).

16561625161 is an equidigital number, since it uses as much as digits as its factorization.

16561625161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 40.

The spelling of 16561625161 in words is "sixteen billion, five hundred sixty-one million, six hundred twenty-five thousand, one hundred sixty-one".