217066813 has 2 divisors, whose sum is σ = 217066814. Its totient is φ = 217066812.

The previous prime is 217066793. The next prime is 217066909. The reversal of 217066813 is 318660712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121066009 + 96000804 = 11003^2 + 9798^2 .

It is a cyclic number.

It is not a de Polignac number, because 217066813 - 2⁹ = 217066301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (214066813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108533406 + 108533407.

It is an arithmetic number, because the mean of its divisors is an integer number (108533407).

Almost surely, 2^217066813 is an apocalyptic number.

It is an amenable number.

217066813 is a deficient number, since it is larger than the sum of its proper divisors (1).

217066813 is an equidigital number, since it uses as much as digits as its factorization.

217066813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 217066813 is about 14733.1874691120. The cubic root of 217066813 is about 600.9861680478.

The spelling of 217066813 in words is "two hundred seventeen million, sixty-six thousand, eight hundred thirteen".