205644734081 has 2 divisors, whose sum is σ = 205644734082. Its totient is φ = 205644734080.

The previous prime is 205644734051. The next prime is 205644734213. The reversal of 205644734081 is 180437446502.

It is a happy number.

205644734081 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., 128938446400 + 76706287681 = 359080^2 + 276959^2 .

It is a cyclic number.

It is not a de Polignac number, because 205644734081 - 2²² = 205640539777 is a prime.

It is a super-2 number, since 2×205644734081² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (205644734011) 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, 102822367040 + 102822367041.

It is an arithmetic number, because the mean of its divisors is an integer number (102822367041).

Almost surely, 2^205644734081 is an apocalyptic number.

It is an amenable number.

205644734081 is a deficient number, since it is larger than the sum of its proper divisors (1).

205644734081 is an equidigital number, since it uses as much as digits as its factorization.

205644734081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 645120, while the sum is 44.

The spelling of 205644734081 in words is "two hundred five billion, six hundred forty-four million, seven hundred thirty-four thousand, eighty-one".