205681057 has 2 divisors, whose sum is σ = 205681058. Its totient is φ = 205681056.

The previous prime is 205681043. The next prime is 205681067. The reversal of 205681057 is 750186502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172029456 + 33651601 = 13116^2 + 5801^2 .

It is a cyclic number.

It is not a de Polignac number, because 205681057 - 2¹⁹ = 205156769 is a prime.

It is not a weakly prime, because it can be changed into another prime (205681037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102840528 + 102840529.

It is an arithmetic number, because the mean of its divisors is an integer number (102840529).

Almost surely, 2^205681057 is an apocalyptic number.

It is an amenable number.

205681057 is a deficient number, since it is larger than the sum of its proper divisors (1).

205681057 is an equidigital number, since it uses as much as digits as its factorization.

205681057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 205681057 is about 14341.5848845237. The cubic root of 205681057 is about 590.2891018285.

Subtracting 205681057 from its reverse (750186502), we obtain a palindrome (544505445).

The spelling of 205681057 in words is "two hundred five million, six hundred eighty-one thousand, fifty-seven".