666561572115 has 16 divisors (see below), whose sum is σ = 1066513651200. Its totient is φ = 355494459872.

The previous prime is 666561572099. The next prime is 666561572119. The reversal of 666561572115 is 511275165666.

It is a cyclic number.

It is not a de Polignac number, because 666561572115 - 2⁴ = 666561572099 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666561572119) 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 15 ways as a sum of consecutive naturals, for example, 937366 + ... + 1487204.

It is an arithmetic number, because the mean of its divisors is an integer number (66657103200).

Almost surely, 2^666561572115 is an apocalyptic number.

666561572115 is a deficient number, since it is larger than the sum of its proper divisors (399952079085).

666561572115 is a wasteful number, since it uses less digits than its factorization.

666561572115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630666.

The product of its digits is 2268000, while the sum is 51.

The spelling of 666561572115 in words is "six hundred sixty-six billion, five hundred sixty-one million, five hundred seventy-two thousand, one hundred fifteen".