66686440808 has 32 divisors (see below), whose sum is σ = 134875108200. Its totient is φ = 30728118528.

The previous prime is 66686440783. The next prime is 66686440853. The reversal of 66686440808 is 80804468666.

It is a happy number.

66686440808 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 4 ways, for example, as 34953293764 + 31733147044 = 186958^2 + 178138^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 459263 + ... + 586766.

Almost surely, 2^66686440808 is an apocalyptic number.

It is an amenable number.

66686440808 is an abundant number, since it is smaller than the sum of its proper divisors (68188667392).

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

66686440808 is a wasteful number, since it uses less digits than its factorization.

66686440808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046661 (or 1046657 counting only the distinct ones).

The product of its (nonzero) digits is 10616832, while the sum is 56.

The spelling of 66686440808 in words is "sixty-six billion, six hundred eighty-six million, four hundred forty thousand, eight hundred eight".