666923 has 4 divisors (see below), whose sum is σ = 669240. Its totient is φ = 664608.

The previous prime is 666901. The next prime is 666929. The reversal of 666923 is 329666.

666923 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666923 - 2⁸ = 666667 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666923.

It is not an unprimeable number, because it can be changed into a prime (666929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 653 + ... + 1326.

It is an arithmetic number, because the mean of its divisors is an integer number (167310).

2⁶⁶⁶⁹²³ is an apocalyptic number.

666923 is a deficient number, since it is larger than the sum of its proper divisors (2317).

666923 is a wasteful number, since it uses less digits than its factorization.

666923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2316.

The product of its digits is 11664, while the sum is 32.

The square root of 666923 is about 816.6535373094. The cubic root of 666923 is about 87.3692414286.

The spelling of 666923 in words is "six hundred sixty-six thousand, nine hundred twenty-three".