66605665600 has 42 divisors (see below), whose sum is σ = 163891569854. Its totient is φ = 26642265600.

The previous prime is 66605665591. The next prime is 66605665601. The reversal of 66605665600 is 656650666.

It can be written as a sum of positive squares in 3 ways, for example, as 3656862784 + 62948802816 = 60472^2 + 250896^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66605665601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 20812671 + ... + 20815870.

Almost surely, 2^66605665600 is an apocalyptic number.

It is an amenable number.

66605665600 is an abundant number, since it is smaller than the sum of its proper divisors (97285904254).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66605665600 is a wasteful number, since it uses less digits than its factorization.

66605665600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41628563 (or 41628548 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 46.

The spelling of 66605665600 in words is "sixty-six billion, six hundred five million, six hundred sixty-five thousand, six hundred".