66555166666 has 16 divisors (see below), whose sum is σ = 101691471240. Its totient is φ = 32660398080.

The previous prime is 66555166661. The next prime is 66555166669. The reversal of 66555166666 is 66666155566.

It can be written as a sum of positive squares in 4 ways, for example, as 57808989225 + 8746177441 = 240435^2 + 93521^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66555166666.

It is not an unprimeable number, because it can be changed into a prime (66555166661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 541111 + ... + 652618.

Almost surely, 2^66555166666 is an apocalyptic number.

66555166666 is a deficient number, since it is larger than the sum of its proper divisors (35136304574).

66555166666 is a wasteful number, since it uses less digits than its factorization.

66555166666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1194249.

The product of its digits is 34992000, while the sum is 58.

The spelling of 66555166666 in words is "sixty-six billion, five hundred fifty-five million, one hundred sixty-six thousand, six hundred sixty-six".