866085709 has 2 divisors, whose sum is σ = 866085710. Its totient is φ = 866085708.

The previous prime is 866085707. The next prime is 866085739. The reversal of 866085709 is 907580668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 836077225 + 30008484 = 28915^2 + 5478^2 .

It is a cyclic number.

It is not a de Polignac number, because 866085709 - 2¹ = 866085707 is a prime.

Together with 866085707, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866085707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433042854 + 433042855.

It is an arithmetic number, because the mean of its divisors is an integer number (433042855).

Almost surely, 2^866085709 is an apocalyptic number.

It is an amenable number.

866085709 is a deficient number, since it is larger than the sum of its proper divisors (1).

866085709 is an equidigital number, since it uses as much as digits as its factorization.

866085709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 49.

The square root of 866085709 is about 29429.3341582850. The cubic root of 866085709 is about 953.2064173095.

The spelling of 866085709 in words is "eight hundred sixty-six million, eighty-five thousand, seven hundred nine".