666365123 has 4 divisors (see below), whose sum is σ = 671229240. Its totient is φ = 661501008.

The previous prime is 666365113. The next prime is 666365137. The reversal of 666365123 is 321563666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 321563666 = 2 ⋅160781833.

It is a cyclic number.

It is not a de Polignac number, because 666365123 - 2⁶ = 666365059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666365113) 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 3 ways as a sum of consecutive naturals, for example, 2431853 + ... + 2432126.

It is an arithmetic number, because the mean of its divisors is an integer number (167807310).

Almost surely, 2^666365123 is an apocalyptic number.

666365123 is a deficient number, since it is larger than the sum of its proper divisors (4864117).

666365123 is a wasteful number, since it uses less digits than its factorization.

666365123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4864116.

The product of its digits is 116640, while the sum is 38.

The square root of 666365123 is about 25814.0489462618. The cubic root of 666365123 is about 873.4487335447.

The spelling of 666365123 in words is "six hundred sixty-six million, three hundred sixty-five thousand, one hundred twenty-three".