666561056611 has 8 divisors (see below), whose sum is σ = 672819960384. Its totient is φ = 660331197120.

The previous prime is 666561056561. The next prime is 666561056617. The reversal of 666561056611 is 116650165666.

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 666561056611 - 2⁹ = 666561056099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666561056617) 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, 7214955 + ... + 7306756.

It is an arithmetic number, because the mean of its divisors is an integer number (84102495048).

Almost surely, 2^666561056611 is an apocalyptic number.

666561056611 is a deficient number, since it is larger than the sum of its proper divisors (6258903773).

666561056611 is a wasteful number, since it uses less digits than its factorization.

666561056611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14522141.

The product of its (nonzero) digits is 1166400, while the sum is 49.

The spelling of 666561056611 in words is "six hundred sixty-six billion, five hundred sixty-one million, fifty-six thousand, six hundred eleven".