21668068805 has 16 divisors (see below), whose sum is σ = 26363473920. Its totient is φ = 17094897792.

The previous prime is 21668068801. The next prime is 21668068819. The reversal of 21668068805 is 50886086612.

It is a cyclic number.

It is not a de Polignac number, because 21668068805 - 2² = 21668068801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21668068801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3881 + ... + 208209.

It is an arithmetic number, because the mean of its divisors is an integer number (1647717120).

Almost surely, 2^21668068805 is an apocalyptic number.

It is an amenable number.

21668068805 is a deficient number, since it is larger than the sum of its proper divisors (4695405115).

21668068805 is a wasteful number, since it uses less digits than its factorization.

21668068805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204628.

The product of its (nonzero) digits is 1105920, while the sum is 50.

The spelling of 21668068805 in words is "twenty-one billion, six hundred sixty-eight million, sixty-eight thousand, eight hundred five".