66659895666 has 144 divisors (see below), whose sum is σ = 181127052288. Its totient is φ = 17561880000.

The previous prime is 66659895641. The next prime is 66659895671.

66659895666 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 66659895594 and 66659895603.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 13194841 + ... + 13199891.

It is an arithmetic number, because the mean of its divisors is an integer number (1257826752).

Almost surely, 2^66659895666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66659895666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90563526144).

66659895666 is an abundant number, since it is smaller than the sum of its proper divisors (114467156622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66659895666 is a wasteful number, since it uses less digits than its factorization.

66659895666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6237 (or 6227 counting only the distinct ones).

The product of its digits is 755827200, while the sum is 72.

The spelling of 66659895666 in words is "sixty-six billion, six hundred fifty-nine million, eight hundred ninety-five thousand, six hundred sixty-six".