666565456123 has 32 divisors (see below), whose sum is σ = 773779046400. Its totient is φ = 562412353536.

The previous prime is 666565456079. The next prime is 666565456133. The reversal of 666565456123 is 321654565666.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666565456123 is a prime.

It is a super-2 number, since 2×666565456123² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666565456133) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 147696715 + ... + 147701227.

It is an arithmetic number, because the mean of its divisors is an integer number (24180595200).

Almost surely, 2^666565456123 is an apocalyptic number.

666565456123 is a deficient number, since it is larger than the sum of its proper divisors (107213590277).

666565456123 is a wasteful number, since it uses less digits than its factorization.

666565456123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5611.

The product of its digits is 23328000, while the sum is 55.

The spelling of 666565456123 in words is "six hundred sixty-six billion, five hundred sixty-five million, four hundred fifty-six thousand, one hundred twenty-three".