11555505566 has 24 divisors (see below), whose sum is σ = 19080837552. Its totient is φ = 5244624000.

The previous prime is 11555505551. The next prime is 11555505589. The reversal of 11555505566 is 66550555511.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 127391 + ... + 198341.

It is an arithmetic number, because the mean of its divisors is an integer number (795034898).

Almost surely, 2^11555505566 is an apocalyptic number.

11555505566 is a deficient number, since it is larger than the sum of its proper divisors (7525331986).

11555505566 is a wasteful number, since it uses less digits than its factorization.

11555505566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71648 (or 71637 counting only the distinct ones).

The product of its (nonzero) digits is 562500, while the sum is 44.

The spelling of 11555505566 in words is "eleven billion, five hundred fifty-five million, five hundred five thousand, five hundred sixty-six".