666222665561 has 8 divisors (see below), whose sum is σ = 701294664000. Its totient is φ = 631151431920.

The previous prime is 666222665551. The next prime is 666222665579. The reversal of 666222665561 is 165566222666.

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 666222665561 - 2¹⁸ = 666222403417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666222665551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2784491 + ... + 3014271.

It is an arithmetic number, because the mean of its divisors is an integer number (87661833000).

Almost surely, 2^666222665561 is an apocalyptic number.

It is an amenable number.

666222665561 is a deficient number, since it is larger than the sum of its proper divisors (35071998439).

666222665561 is a wasteful number, since it uses less digits than its factorization.

666222665561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382399.

The product of its digits is 9331200, while the sum is 53.

The spelling of 666222665561 in words is "six hundred sixty-six billion, two hundred twenty-two million, six hundred sixty-five thousand, five hundred sixty-one".