221066717 has 2 divisors, whose sum is σ = 221066718. Its totient is φ = 221066716.

The previous prime is 221066693. The next prime is 221066719. The reversal of 221066717 is 717660122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205234276 + 15832441 = 14326^2 + 3979^2 .

It is a cyclic number.

It is not a de Polignac number, because 221066717 - 2²² = 216872413 is a prime.

Together with 221066719, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221066719) 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, 110533358 + 110533359.

It is an arithmetic number, because the mean of its divisors is an integer number (110533359).

Almost surely, 2^221066717 is an apocalyptic number.

It is an amenable number.

221066717 is a deficient number, since it is larger than the sum of its proper divisors (1).

221066717 is an equidigital number, since it uses as much as digits as its factorization.

221066717 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 221066717 is about 14868.3125135302. The cubic root of 221066717 is about 604.6551931812.

The spelling of 221066717 in words is "two hundred twenty-one million, sixty-six thousand, seven hundred seventeen".