6666018661 has 8 divisors (see below), whose sum is σ = 6957448344. Its totient is φ = 6380724480.

The previous prime is 6666018659. The next prime is 6666018673. The reversal of 6666018661 is 1668106666.

It can be written as a sum of positive squares in 4 ways, for example, as 1211457636 + 5454561025 = 34806^2 + 73855^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 6666018661 - 2¹ = 6666018659 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 (6666018641) 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 7 ways as a sum of consecutive naturals, for example, 1531656 + ... + 1536001.

It is an arithmetic number, because the mean of its divisors is an integer number (869681043).

Almost surely, 2^6666018661 is an apocalyptic number.

It is an amenable number.

6666018661 is a deficient number, since it is larger than the sum of its proper divisors (291429683).

6666018661 is a wasteful number, since it uses less digits than its factorization.

6666018661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3067751.

The product of its (nonzero) digits is 373248, while the sum is 46.

The square root of 6666018661 is about 81645.6897882552. The cubic root of 6666018661 is about 1882.0110761183.

The spelling of 6666018661 in words is "six billion, six hundred sixty-six million, eighteen thousand, six hundred sixty-one".