208131894607717 has 2 divisors, whose sum is σ = 208131894607718. Its totient is φ = 208131894607716.

The previous prime is 208131894607697. The next prime is 208131894607733. The reversal of 208131894607717 is 717706498131802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157411375084161 + 50720519523556 = 12546369^2 + 7121834^2 .

It is a cyclic number.

It is not a de Polignac number, because 208131894607717 - 2¹⁹ = 208131894083429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208131894601717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104065947303858 + 104065947303859.

It is an arithmetic number, because the mean of its divisors is an integer number (104065947303859).

Almost surely, 2^{208131894607717} is an apocalyptic number.

It is an amenable number.

208131894607717 is a deficient number, since it is larger than the sum of its proper divisors (1).

208131894607717 is an equidigital number, since it uses as much as digits as its factorization.

208131894607717 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28449792, while the sum is 64.

The spelling of 208131894607717 in words is "two hundred eight trillion, one hundred thirty-one billion, eight hundred ninety-four million, six hundred seven thousand, seven hundred seventeen".