66808256866 has 8 divisors (see below), whose sum is σ = 107921030364. Its totient is φ = 30834580080.

The previous prime is 66808256861. The next prime is 66808256903. The reversal of 66808256866 is 66865280866.

It can be written as a sum of positive squares in 2 ways, for example, as 50683066641 + 16125190225 = 225129^2 + 126985^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×66808256866³ (a number of 33 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (66808256861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1284774145 + ... + 1284774196.

Almost surely, 2^66808256866 is an apocalyptic number.

66808256866 is a deficient number, since it is larger than the sum of its proper divisors (41112773498).

66808256866 is a wasteful number, since it uses less digits than its factorization.

66808256866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2569548356.

The product of its (nonzero) digits is 39813120, while the sum is 61.

The spelling of 66808256866 in words is "sixty-six billion, eight hundred eight million, two hundred fifty-six thousand, eight hundred sixty-six".