21060865645665 has 64 divisors (see below), whose sum is σ = 36568912064256. Its totient is φ = 10309026373632.

The previous prime is 21060865645643. The next prime is 21060865645667. The reversal of 21060865645665 is 56654656806012.

It is not a de Polignac number, because 21060865645665 - 2¹⁰ = 21060865644641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21060865645599 and 21060865645608.

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 63 ways as a sum of consecutive naturals, for example, 5154877 + ... + 8288213.

It is an arithmetic number, because the mean of its divisors is an integer number (571389251004).

Almost surely, 2^{21060865645665} is an apocalyptic number.

It is an amenable number.

21060865645665 is a deficient number, since it is larger than the sum of its proper divisors (15508046418591).

21060865645665 is a wasteful number, since it uses less digits than its factorization.

21060865645665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3134018.

The product of its (nonzero) digits is 62208000, while the sum is 60.

The spelling of 21060865645665 in words is "twenty-one trillion, sixty billion, eight hundred sixty-five million, six hundred forty-five thousand, six hundred sixty-five".