866405382409 has 4 divisors (see below), whose sum is σ = 990177579904. Its totient is φ = 742633184916.

The previous prime is 866405382391. The next prime is 866405382421. The reversal of 866405382409 is 904283504668.

866405382409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 866405382409 - 2¹⁷ = 866405251337 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 866405382409.

It is not an unprimeable number, because it can be changed into a prime (866405382439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61886098737 + ... + 61886098750.

It is an arithmetic number, because the mean of its divisors is an integer number (247544394976).

Almost surely, 2^866405382409 is an apocalyptic number.

It is an amenable number.

866405382409 is a deficient number, since it is larger than the sum of its proper divisors (123772197495).

866405382409 is a wasteful number, since it uses less digits than its factorization.

866405382409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123772197494.

The product of its (nonzero) digits is 9953280, while the sum is 55.

The spelling of 866405382409 in words is "eight hundred sixty-six billion, four hundred five million, three hundred eighty-two thousand, four hundred nine".