205458016817 has 2 divisors, whose sum is σ = 205458016818. Its totient is φ = 205458016816.

The previous prime is 205458016811. The next prime is 205458016843. The reversal of 205458016817 is 718610854502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143634178081 + 61823838736 = 378991^2 + 248644^2 .

It is a cyclic number.

It is not a de Polignac number, because 205458016817 - 2¹⁸ = 205457754673 is a prime.

It is a super-2 number, since 2×205458016817² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (205458016811) 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, 102729008408 + 102729008409.

It is an arithmetic number, because the mean of its divisors is an integer number (102729008409).

Almost surely, 2^205458016817 is an apocalyptic number.

It is an amenable number.

205458016817 is a deficient number, since it is larger than the sum of its proper divisors (1).

205458016817 is an equidigital number, since it uses as much as digits as its factorization.

205458016817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 537600, while the sum is 47.

The spelling of 205458016817 in words is "two hundred five billion, four hundred fifty-eight million, sixteen thousand, eight hundred seventeen".