21060865645666 has 64 divisors (see below), whose sum is σ = 40452537680640. Its totient is φ = 7983468380160.

The previous prime is 21060865645643. The next prime is 21060865645667. The reversal of 21060865645666 is 66654656806012.

It is not an unprimeable number, because it can be changed into a prime (21060865645667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 215842746 + ... + 215940298.

It is an arithmetic number, because the mean of its divisors is an integer number (632070901260).

Almost surely, 2^{21060865645666} is an apocalyptic number.

21060865645666 is a deficient number, since it is larger than the sum of its proper divisors (19391672034974).

21060865645666 is a wasteful number, since it uses less digits than its factorization.

21060865645666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135499.

The product of its (nonzero) digits is 74649600, while the sum is 61.

The spelling of 21060865645666 in words is "twenty-one trillion, sixty billion, eight hundred sixty-five million, six hundred forty-five thousand, six hundred sixty-six".