66617313993 has 18 divisors (see below), whose sum is σ = 102218266254. Its totient is φ = 41799097344.

The previous prime is 66617313979. The next prime is 66617314021. The reversal of 66617313993 is 39931371666.

66617313993 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 3 ways, for example, as 32226353289 + 34390960704 = 179517^2 + 185448^2 .

It is not a de Polignac number, because 66617313993 - 2⁹ = 66617313481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66617313943) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 12803496 + ... + 12808697.

Almost surely, 2^66617313993 is an apocalyptic number.

It is an amenable number.

66617313993 is a deficient number, since it is larger than the sum of its proper divisors (35600952261).

66617313993 is a wasteful number, since it uses less digits than its factorization.

66617313993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25612233 (or 25612213 counting only the distinct ones).

The product of its digits is 3306744, while the sum is 54.

The spelling of 66617313993 in words is "sixty-six billion, six hundred seventeen million, three hundred thirteen thousand, nine hundred ninety-three".