205555666501 has 2 divisors, whose sum is σ = 205555666502. Its totient is φ = 205555666500.

The previous prime is 205555666429. The next prime is 205555666597. The reversal of 205555666501 is 105666555502.

205555666501 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., 136012702401 + 69542964100 = 368799^2 + 263710^2 .

It is a cyclic number.

It is not a de Polignac number, because 205555666501 - 2⁷ = 205555666373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205555696501) 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, 102777833250 + 102777833251.

It is an arithmetic number, because the mean of its divisors is an integer number (102777833251).

Almost surely, 2^205555666501 is an apocalyptic number.

It is an amenable number.

205555666501 is a deficient number, since it is larger than the sum of its proper divisors (1).

205555666501 is an equidigital number, since it uses as much as digits as its factorization.

205555666501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1350000, while the sum is 46.

The spelling of 205555666501 in words is "two hundred five billion, five hundred fifty-five million, six hundred sixty-six thousand, five hundred one".