66517215109 has 2 divisors, whose sum is σ = 66517215110. Its totient is φ = 66517215108.

The previous prime is 66517215091. The next prime is 66517215139. The reversal of 66517215109 is 90151271566.

Together with previous prime (66517215091) 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., 51152868900 + 15364346209 = 226170^2 + 123953^2 .

It is a cyclic number.

It is not a de Polignac number, because 66517215109 - 2⁵ = 66517215077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66517215139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33258607554 + 33258607555.

It is an arithmetic number, because the mean of its divisors is an integer number (33258607555).

Almost surely, 2^66517215109 is an apocalyptic number.

It is an amenable number.

66517215109 is a deficient number, since it is larger than the sum of its proper divisors (1).

66517215109 is an equidigital number, since it uses as much as digits as its factorization.

66517215109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 43.

The spelling of 66517215109 in words is "sixty-six billion, five hundred seventeen million, two hundred fifteen thousand, one hundred nine".