21104664564566 has 8 divisors (see below), whose sum is σ = 34534905651144. Its totient is φ = 9593029347520.

The previous prime is 21104664564517. The next prime is 21104664564587. The reversal of 21104664564566 is 66546546640112.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 479651467355 + ... + 479651467398.

It is an arithmetic number, because the mean of its divisors is an integer number (4316863206393).

Almost surely, 2^{21104664564566} is an apocalyptic number.

21104664564566 is a deficient number, since it is larger than the sum of its proper divisors (13430241086578).

21104664564566 is a wasteful number, since it uses less digits than its factorization.

21104664564566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 959302934766.

The product of its (nonzero) digits is 24883200, while the sum is 56.

The spelling of 21104664564566 in words is "twenty-one trillion, one hundred four billion, six hundred sixty-four million, five hundred sixty-four thousand, five hundred sixty-six".