66321217 has 2 divisors, whose sum is σ = 66321218. Its totient is φ = 66321216.

The previous prime is 66321197. The next prime is 66321271. The reversal of 66321217 is 71212366.

Together with next prime (66321271) 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., 58430736 + 7890481 = 7644^2 + 2809^2 .

It is a cyclic number.

It is not a de Polignac number, because 66321217 - 2¹⁵ = 66288449 is a prime.

It is a super-2 number, since 2×66321217² = 8797007648722178, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66321317) 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, 33160608 + 33160609.

It is an arithmetic number, because the mean of its divisors is an integer number (33160609).

Almost surely, 2^66321217 is an apocalyptic number.

It is an amenable number.

66321217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66321217 is an equidigital number, since it uses as much as digits as its factorization.

66321217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

The square root of 66321217 is about 8143.7839485094. The cubic root of 66321217 is about 404.7785549556.

The spelling of 66321217 in words is "sixty-six million, three hundred twenty-one thousand, two hundred seventeen".