866844206649 has 20 divisors (see below), whose sum is σ = 1295761402320. Its totient is φ = 577518591960.

The previous prime is 866844206647. The next prime is 866844206653. The reversal of 866844206649 is 946602448668.

It is not a de Polignac number, because 866844206649 - 2¹ = 866844206647 is a prime.

It is not an unprimeable number, because it can be changed into a prime (866844206647) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3371019 + ... + 3619040.

It is an arithmetic number, because the mean of its divisors is an integer number (64788070116).

Almost surely, 2^866844206649 is an apocalyptic number.

It is an amenable number.

866844206649 is a deficient number, since it is larger than the sum of its proper divisors (428917195671).

866844206649 is a wasteful number, since it uses less digits than its factorization.

866844206649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6991602 (or 6991593 counting only the distinct ones).

The product of its (nonzero) digits is 95551488, while the sum is 63.

The spelling of 866844206649 in words is "eight hundred sixty-six billion, eight hundred forty-four million, two hundred six thousand, six hundred forty-nine".