666623423 has 2 divisors, whose sum is σ = 666623424. Its totient is φ = 666623422.

The previous prime is 666623369. The next prime is 666623443. The reversal of 666623423 is 324326666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666623423 - 2¹⁰ = 666622399 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666623443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333311711 + 333311712.

It is an arithmetic number, because the mean of its divisors is an integer number (333311712).

Almost surely, 2^666623423 is an apocalyptic number.

666623423 is a deficient number, since it is larger than the sum of its proper divisors (1).

666623423 is an equidigital number, since it uses as much as digits as its factorization.

666623423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 38.

The square root of 666623423 is about 25819.0515511318. The cubic root of 666623423 is about 873.5615759167.

The spelling of 666623423 in words is "six hundred sixty-six million, six hundred twenty-three thousand, four hundred twenty-three".