66565855856566 has 128 divisors (see below), whose sum is σ = 121794929994240. Its totient is φ = 26891646566400.

The previous prime is 66565855856497. The next prime is 66565855856579.

66565855856566 is nontrivially palindromic in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 66565855856566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11766986010 + ... + 11766991666.

It is an arithmetic number, because the mean of its divisors is an integer number (951522890580).

Almost surely, 2^{66565855856566} is an apocalyptic number.

66565855856566 is a deficient number, since it is larger than the sum of its proper divisors (55229074137674).

66565855856566 is a wasteful number, since it uses less digits than its factorization.

66565855856566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10750.

The product of its digits is 46656000000, while the sum is 82.

The spelling of 66565855856566 in words is "sixty-six trillion, five hundred sixty-five billion, eight hundred fifty-five million, eight hundred fifty-six thousand, five hundred sixty-six".