66555666699965 has 16 divisors (see below), whose sum is σ = 84566100468672. Its totient is φ = 50111759249664.

The previous prime is 66555666699953. The next prime is 66555666700021. The reversal of 66555666699965 is 56999666655566.

It is a cyclic number.

It is not a de Polignac number, because 66555666699965 - 2²⁰ = 66555665651389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2 + ... + 11537388.

It is an arithmetic number, because the mean of its divisors is an integer number (5285381279292).

Almost surely, 2^{66555666699965} is an apocalyptic number.

It is an amenable number.

66555666699965 is a deficient number, since it is larger than the sum of its proper divisors (18010433768707).

66555666699965 is a wasteful number, since it uses less digits than its factorization.

66555666699965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11605276.

The product of its digits is 127545840000, while the sum is 89.

The spelling of 66555666699965 in words is "sixty-six trillion, five hundred fifty-five billion, six hundred sixty-six million, six hundred ninety-nine thousand, nine hundred sixty-five".