18566561644 has 12 divisors (see below), whose sum is σ = 32826447304. Its totient is φ = 9187576704.

The previous prime is 18566561621. The next prime is 18566561731. The reversal of 18566561644 is 44616566581.

It is a super-3 number, since 3×18566561644³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 18566561591 and 18566561600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23925594 + ... + 23926369.

Almost surely, 2^18566561644 is an apocalyptic number.

It is an amenable number.

18566561644 is a deficient number, since it is larger than the sum of its proper divisors (14259885660).

18566561644 is a wasteful number, since it uses less digits than its factorization.

18566561644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47852064 (or 47852062 counting only the distinct ones).

The product of its digits is 4147200, while the sum is 52.

The spelling of 18566561644 in words is "eighteen billion, five hundred sixty-six million, five hundred sixty-one thousand, six hundred forty-four".