11565666656566 has 64 divisors (see below), whose sum is σ = 20176226380800. Its totient is φ = 4916819232000.

The previous prime is 11565666656497. The next prime is 11565666656617. The reversal of 11565666656566 is 66565666656511.

It is a junction number, because it is equal to n+sod(n) for n = 11565666656495 and 11565666656504.

It is a congruent number.

It is an unprimeable number.

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, 414511216 + ... + 414539116.

It is an arithmetic number, because the mean of its divisors is an integer number (315253537200).

Almost surely, 2^{11565666656566} is an apocalyptic number.

11565666656566 is a deficient number, since it is larger than the sum of its proper divisors (8610559724234).

11565666656566 is a wasteful number, since it uses less digits than its factorization.

11565666656566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40565.

The product of its digits is 1049760000, while the sum is 70.

Subtracting 11565666656566 from its reverse (66565666656511), we obtain a palindrome (54999999999945).

The spelling of 11565666656566 in words is "eleven trillion, five hundred sixty-five billion, six hundred sixty-six million, six hundred fifty-six thousand, five hundred sixty-six".