205110061661 has 2 divisors, whose sum is σ = 205110061662. Its totient is φ = 205110061660.

The previous prime is 205110061633. The next prime is 205110061669. The reversal of 205110061661 is 166160011502.

205110061661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161222325625 + 43887736036 = 401525^2 + 209494^2 .

It is a cyclic number.

It is not a de Polignac number, because 205110061661 - 2²⁶ = 205042952797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205110061669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102555030830 + 102555030831.

It is an arithmetic number, because the mean of its divisors is an integer number (102555030831).

Almost surely, 2^205110061661 is an apocalyptic number.

It is an amenable number.

205110061661 is a deficient number, since it is larger than the sum of its proper divisors (1).

205110061661 is an equidigital number, since it uses as much as digits as its factorization.

205110061661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 29.

The spelling of 205110061661 in words is "two hundred five billion, one hundred ten million, sixty-one thousand, six hundred sixty-one".