205666254601 has 2 divisors, whose sum is σ = 205666254602. Its totient is φ = 205666254600.

The previous prime is 205666254527. The next prime is 205666254659. The reversal of 205666254601 is 106452666502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205663157001 + 3097600 = 453501^2 + 1760^2 .

It is a cyclic number.

It is not a de Polignac number, because 205666254601 - 2¹⁷ = 205666123529 is a prime.

It is not a weakly prime, because it can be changed into another prime (205666254301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102833127300 + 102833127301.

It is an arithmetic number, because the mean of its divisors is an integer number (102833127301).

Almost surely, 2^205666254601 is an apocalyptic number.

It is an amenable number.

205666254601 is a deficient number, since it is larger than the sum of its proper divisors (1).

205666254601 is an equidigital number, since it uses as much as digits as its factorization.

205666254601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 205666254601 in words is "two hundred five billion, six hundred sixty-six million, two hundred fifty-four thousand, six hundred one".