66317702560821 has 6 divisors (see below), whose sum is σ = 95792237032310. Its totient is φ = 44211801707208.

The previous prime is 66317702560741. The next prime is 66317702560831. The reversal of 66317702560821 is 12806520771366.

66317702560821 is a `hidden beast` number, since 6 + 6 + 3 + 1 + 7 + 7 + 0 + 2 + 5 + 608 + 21 = 666.

66317702560821 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 only one way, i.e., 66309996179025 + 7706381796 = 8143095^2 + 87786^2 .

It is not a de Polignac number, because 66317702560821 - 2¹⁵ = 66317702528053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66317702560831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3684316808926 + ... + 3684316808943.

Almost surely, 2^{66317702560821} is an apocalyptic number.

It is an amenable number.

66317702560821 is a deficient number, since it is larger than the sum of its proper divisors (29474534471489).

66317702560821 is a wasteful number, since it uses less digits than its factorization.

66317702560821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7368633617875 (or 7368633617872 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 54.

The spelling of 66317702560821 in words is "sixty-six trillion, three hundred seventeen billion, seven hundred two million, five hundred sixty thousand, eight hundred twenty-one".