866654443221 has 8 divisors (see below), whose sum is σ = 1320616294464. Its totient is φ = 495231110400.

The previous prime is 866654443219. The next prime is 866654443243. The reversal of 866654443221 is 122344456668.

It is a happy number.

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

It is not a de Polignac number, because 866654443221 - 2¹ = 866654443219 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866654448221) 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 in 7 ways as a sum of consecutive naturals, for example, 20634629580 + ... + 20634629621.

It is an arithmetic number, because the mean of its divisors is an integer number (165077036808).

Almost surely, 2^866654443221 is an apocalyptic number.

It is an amenable number.

866654443221 is a deficient number, since it is larger than the sum of its proper divisors (453961851243).

866654443221 is a wasteful number, since it uses less digits than its factorization.

866654443221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41269259211.

The product of its digits is 6635520, while the sum is 51.

Adding to 866654443221 its reverse (122344456668), we get a palindrome (988998899889).

The spelling of 866654443221 in words is "eight hundred sixty-six billion, six hundred fifty-four million, four hundred forty-three thousand, two hundred twenty-one".