66688880868 has 36 divisors (see below), whose sum is σ = 169274173068. Its totient is φ = 22137384960.

The previous prime is 66688880827. The next prime is 66688880893. The reversal of 66688880868 is 86808888666.

It can be written as a sum of positive squares in 2 ways, for example, as 57551050404 + 9137830464 = 239898^2 + 95592^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a junction number, because it is equal to n+sod(n) for n = 66688880796 and 66688880805.

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, 3834621 + ... + 3851972.

It is an arithmetic number, because the mean of its divisors is an integer number (4702060363).

Almost surely, 2^66688880868 is an apocalyptic number.

It is an amenable number.

66688880868 is an abundant number, since it is smaller than the sum of its proper divisors (102585292200).

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

66688880868 is a wasteful number, since it uses less digits than its factorization.

66688880868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7686844 (or 7686839 counting only the distinct ones).

The product of its (nonzero) digits is 339738624, while the sum is 72.

The spelling of 66688880868 in words is "sixty-six billion, six hundred eighty-eight million, eight hundred eighty thousand, eight hundred sixty-eight".