985666809217 has 2 divisors, whose sum is σ = 985666809218. Its totient is φ = 985666809216.

The previous prime is 985666809133. The next prime is 985666809221. The reversal of 985666809217 is 712908666589.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 848380997776 + 137285811441 = 921076^2 + 370521^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-985666809217 is a prime.

It is not a weakly prime, because it can be changed into another prime (985666809277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 492833404608 + 492833404609.

It is an arithmetic number, because the mean of its divisors is an integer number (492833404609).

Almost surely, 2^985666809217 is an apocalyptic number.

It is an amenable number.

985666809217 is a deficient number, since it is larger than the sum of its proper divisors (1).

985666809217 is an equidigital number, since it uses as much as digits as its factorization.

985666809217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 78382080, while the sum is 67.

The spelling of 985666809217 in words is "nine hundred eighty-five billion, six hundred sixty-six million, eight hundred nine thousand, two hundred seventeen".