213205257817 has 2 divisors, whose sum is σ = 213205257818. Its totient is φ = 213205257816.

The previous prime is 213205257803. The next prime is 213205257823. The reversal of 213205257817 is 718752502312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 175275358281 + 37929899536 = 418659^2 + 194756^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213205257817 is a prime.

It is not a weakly prime, because it can be changed into another prime (213205257827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106602628908 + 106602628909.

It is an arithmetic number, because the mean of its divisors is an integer number (106602628909).

Almost surely, 2^213205257817 is an apocalyptic number.

It is an amenable number.

213205257817 is a deficient number, since it is larger than the sum of its proper divisors (1).

213205257817 is an equidigital number, since it uses as much as digits as its factorization.

213205257817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 235200, while the sum is 43.

The spelling of 213205257817 in words is "two hundred thirteen billion, two hundred five million, two hundred fifty-seven thousand, eight hundred seventeen".