866684309 has 2 divisors, whose sum is σ = 866684310. Its totient is φ = 866684308.

The previous prime is 866684303. The next prime is 866684311. The reversal of 866684309 is 903486668.

866684309 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 865654084 + 1030225 = 29422^2 + 1015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866684309 is a prime.

It is a super-2 number, since 2×866684309² = 1502283382933614962, which contains 22 as substring.

Together with 866684311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866684303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433342154 + 433342155.

It is an arithmetic number, because the mean of its divisors is an integer number (433342155).

Almost surely, 2^866684309 is an apocalyptic number.

It is an amenable number.

866684309 is a deficient number, since it is larger than the sum of its proper divisors (1).

866684309 is an equidigital number, since it uses as much as digits as its factorization.

866684309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1492992, while the sum is 50.

The square root of 866684309 is about 29439.5025263675. The cubic root of 866684309 is about 953.4259713908.

The spelling of 866684309 in words is "eight hundred sixty-six million, six hundred eighty-four thousand, three hundred nine".