21666364556233 has 16 divisors (see below), whose sum is σ = 22694696121600. Its totient is φ = 20645241390400.

The previous prime is 21666364556209. The next prime is 21666364556273. The reversal of 21666364556233 is 33265546366612.

It is a cyclic number.

It is not a de Polignac number, because 21666364556233 - 2¹⁷ = 21666364425161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21666364556203) 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, 63562308 + ... + 63902266.

It is an arithmetic number, because the mean of its divisors is an integer number (1418418507600).

Almost surely, 2^{21666364556233} is an apocalyptic number.

21666364556233 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21666364556233 is a deficient number, since it is larger than the sum of its proper divisors (1028331565367).

21666364556233 is a wasteful number, since it uses less digits than its factorization.

21666364556233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350552.

The product of its digits is 83980800, while the sum is 58.

The spelling of 21666364556233 in words is "twenty-one trillion, six hundred sixty-six billion, three hundred sixty-four million, five hundred fifty-six thousand, two hundred thirty-three".