866209109 has 8 divisors (see below), whose sum is σ = 941951448. Its totient is φ = 793221120.

The previous prime is 866209093. The next prime is 866209111. The reversal of 866209109 is 901902668.

866209109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 381108484 + 485100625 = 19522^2 + 22025^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 866209109 - 2⁴ = 866209093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866209199) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 687932 + ... + 689189.

It is an arithmetic number, because the mean of its divisors is an integer number (117743931).

Almost surely, 2^866209109 is an apocalyptic number.

It is an amenable number.

866209109 is a deficient number, since it is larger than the sum of its proper divisors (75742339).

866209109 is a wasteful number, since it uses less digits than its factorization.

866209109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1377175.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 866209109 is about 29431.4306312147. The cubic root of 866209109 is about 953.2516861494.

The spelling of 866209109 in words is "eight hundred sixty-six million, two hundred nine thousand, one hundred nine".