66685658666 has 12 divisors (see below), whose sum is σ = 109948669026. Its totient is φ = 30311662920.

The previous prime is 66685658657. The next prime is 66685658701.

66685658666 is nontrivially palindromic in base 10.

66685658666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 61556091025 + 5129567641 = 248105^2 + 71621^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66685658596 and 66685658605.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 137780045 + ... + 137780528.

Almost surely, 2^66685658666 is an apocalyptic number.

66685658666 is a deficient number, since it is larger than the sum of its proper divisors (43263010360).

66685658666 is a wasteful number, since it uses less digits than its factorization.

66685658666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275560597 (or 275560586 counting only the distinct ones).

The product of its digits is 447897600, while the sum is 68.

The spelling of 66685658666 in words is "sixty-six billion, six hundred eighty-five million, six hundred fifty-eight thousand, six hundred sixty-six".