665560666 has 8 divisors (see below), whose sum is σ = 1000026324. Its totient is φ = 332218560.

The previous prime is 665560663. The next prime is 665560703. The reversal of 665560666 is 666065566.

It can be written as a sum of positive squares in 2 ways, for example, as 606193641 + 59367025 = 24621^2 + 7705^2 .

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

It is not an unprimeable number, because it can be changed into a prime (665560663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279405 + ... + 281776.

Almost surely, 2^665560666 is an apocalyptic number.

665560666 is a deficient number, since it is larger than the sum of its proper divisors (334465658).

665560666 is a wasteful number, since it uses less digits than its factorization.

665560666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561776.

The product of its (nonzero) digits is 1166400, while the sum is 46.

The square root of 665560666 is about 25798.4624735661. The cubic root of 665560666 is about 873.0971070525.

The spelling of 665560666 in words is "six hundred sixty-five million, five hundred sixty thousand, six hundred sixty-six".