66666665639 has 16 divisors (see below), whose sum is σ = 82548373248. Its totient is φ = 52530774912.

The previous prime is 66666665633. The next prime is 66666665641. The reversal of 66666665639 is 93656666666.

It is not a de Polignac number, because 66666665639 - 2³² = 62371698343 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 (66666665633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6509117 + ... + 6519350.

It is an arithmetic number, because the mean of its divisors is an integer number (5159273328).

Almost surely, 2^66666665639 is an apocalyptic number.

66666665639 is a deficient number, since it is larger than the sum of its proper divisors (15881707609).

66666665639 is a wasteful number, since it uses less digits than its factorization.

66666665639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13028534.

The product of its digits is 226748160, while the sum is 65.

The spelling of 66666665639 in words is "sixty-six billion, six hundred sixty-six million, six hundred sixty-five thousand, six hundred thirty-nine".