6660220666 has 12 divisors (see below), whose sum is σ = 10981108026. Its totient is φ = 3027372920.

The previous prime is 6660220643. The next prime is 6660220667.

6660220666 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 5752464025 + 907756641 = 75845^2 + 30129^2 .

It is not an unprimeable number, because it can be changed into a prime (6660220667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13760545 + ... + 13761028.

Almost surely, 2^6660220666 is an apocalyptic number.

6660220666 is a deficient number, since it is larger than the sum of its proper divisors (4320887360).

6660220666 is a wasteful number, since it uses less digits than its factorization.

6660220666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27521597 (or 27521586 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 6660220666 is about 81610.1750151291. The cubic root of 6660220666 is about 1881.4652702654.

The spelling of 6660220666 in words is "six billion, six hundred sixty million, two hundred twenty thousand, six hundred sixty-six".