66656015556517 has 4 divisors (see below), whose sum is σ = 66712937859616. Its totient is φ = 66599093253420.

The previous prime is 66656015556499. The next prime is 66656015556521. The reversal of 66656015556517 is 71565551065666.

It is a happy number.

66656015556517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66656015556517 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 (66656015556547) 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 3 ways as a sum of consecutive naturals, for example, 28461149793 + ... + 28461152134.

It is an arithmetic number, because the mean of its divisors is an integer number (16678234464904).

Almost surely, 2^{66656015556517} is an apocalyptic number.

It is an amenable number.

66656015556517 is a deficient number, since it is larger than the sum of its proper divisors (56922303099).

66656015556517 is a wasteful number, since it uses less digits than its factorization.

66656015556517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56922303098.

The product of its (nonzero) digits is 170100000, while the sum is 64.

The spelling of 66656015556517 in words is "sixty-six trillion, six hundred fifty-six billion, fifteen million, five hundred fifty-six thousand, five hundred seventeen".