6665640465666 has 128 divisors (see below), whose sum is σ = 16881464517120. Its totient is φ = 1707384655872.

The previous prime is 6665640465661. The next prime is 6665640465721.

6665640465666 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 6665640465597 and 6665640465606.

It is not an unprimeable number, because it can be changed into a prime (6665640465661) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10956330 + ... + 11548698.

It is an arithmetic number, because the mean of its divisors is an integer number (131886441540).

Almost surely, 2^{6665640465666} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6665640465666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8440732258560).

6665640465666 is an abundant number, since it is smaller than the sum of its proper divisors (10215824051454).

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

6665640465666 is a wasteful number, since it uses less digits than its factorization.

6665640465666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592988.

The product of its (nonzero) digits is 671846400, while the sum is 66.

The spelling of 6665640465666 in words is "six trillion, six hundred sixty-five billion, six hundred forty million, four hundred sixty-five thousand, six hundred sixty-six".