66606217 has 2 divisors, whose sum is σ = 66606218. Its totient is φ = 66606216.

The previous prime is 66606209. The next prime is 66606271. The reversal of 66606217 is 71260666.

66606217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with next prime (66606271) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65999376 + 606841 = 8124^2 + 779^2 .

It is a cyclic number.

It is not a de Polignac number, because 66606217 - 2³ = 66606209 is a prime.

It is not a weakly prime, because it can be changed into another prime (66606277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33303108 + 33303109.

It is an arithmetic number, because the mean of its divisors is an integer number (33303109).

Almost surely, 2^66606217 is an apocalyptic number.

It is an amenable number.

66606217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66606217 is an equidigital number, since it uses as much as digits as its factorization.

66606217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 66606217 is about 8161.2631987947. The cubic root of 66606217 is about 405.3575402829.

The spelling of 66606217 in words is "sixty-six million, six hundred six thousand, two hundred seventeen".