866444451021 has 16 divisors (see below), whose sum is σ = 1288002381120. Its totient is φ = 575658196560.

The previous prime is 866444451007. The next prime is 866444451023. The reversal of 866444451021 is 120154444668.

866444451021 is a `hidden beast` number, since 8 + 66 + 44 + 445 + 102 + 1 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-866444451021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866444451023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54754095 + ... + 54769916.

It is an arithmetic number, because the mean of its divisors is an integer number (80500148820).

Almost surely, 2^866444451021 is an apocalyptic number.

It is an amenable number.

866444451021 is a deficient number, since it is larger than the sum of its proper divisors (421557930099).

866444451021 is a wasteful number, since it uses less digits than its factorization.

866444451021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109524313 (or 109524307 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

Adding to 866444451021 its reverse (120154444668), we get a palindrome (986598895689).

The spelling of 866444451021 in words is "eight hundred sixty-six billion, four hundred forty-four million, four hundred fifty-one thousand, twenty-one".