66668781513 has 8 divisors (see below), whose sum is σ = 89113385376. Its totient is φ = 44335016000.

The previous prime is 66668781451. The next prime is 66668781551. The reversal of 66668781513 is 31518786666.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66668781513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66668781013) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27708183 + ... + 27710588.

It is an arithmetic number, because the mean of its divisors is an integer number (11139173172).

Almost surely, 2^66668781513 is an apocalyptic number.

It is an amenable number.

66668781513 is a deficient number, since it is larger than the sum of its proper divisors (22444603863).

66668781513 is a wasteful number, since it uses less digits than its factorization.

66668781513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55419175.

The product of its digits is 8709120, while the sum is 57.

The spelling of 66668781513 in words is "sixty-six billion, six hundred sixty-eight million, seven hundred eighty-one thousand, five hundred thirteen".