65681593645 has 4 divisors (see below), whose sum is σ = 78817912380. Its totient is φ = 52545274912.

The previous prime is 65681593619. The next prime is 65681593651. The reversal of 65681593645 is 54639518656.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27589874404 + 38091719241 = 166102^2 + 195171^2 .

It is a cyclic number.

It is not a de Polignac number, because 65681593645 - 2¹¹ = 65681591597 is a prime.

It is a super-4 number, since 4×65681593645⁴ (a number of 44 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a self number, because there is not a number n which added to its sum of digits gives 65681593645.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6568159360 + ... + 6568159369.

It is an arithmetic number, because the mean of its divisors is an integer number (19704478095).

Almost surely, 2^65681593645 is an apocalyptic number.

It is an amenable number.

65681593645 is a deficient number, since it is larger than the sum of its proper divisors (13136318735).

65681593645 is a wasteful number, since it uses less digits than its factorization.

65681593645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13136318734.

The product of its digits is 23328000, while the sum is 58.

The spelling of 65681593645 in words is "sixty-five billion, six hundred eighty-one million, five hundred ninety-three thousand, six hundred forty-five".