665918923 has 2 divisors, whose sum is σ = 665918924. Its totient is φ = 665918922.

The previous prime is 665918881. The next prime is 665918987. The reversal of 665918923 is 329819566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665918923 - 2¹⁷ = 665787851 is a prime.

It is not a weakly prime, because it can be changed into another prime (665918623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332959461 + 332959462.

It is an arithmetic number, because the mean of its divisors is an integer number (332959462).

Almost surely, 2^665918923 is an apocalyptic number.

665918923 is a deficient number, since it is larger than the sum of its proper divisors (1).

665918923 is an equidigital number, since it uses as much as digits as its factorization.

665918923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 49.

The square root of 665918923 is about 25805.4049183500. The cubic root of 665918923 is about 873.2537354210.

The spelling of 665918923 in words is "six hundred sixty-five million, nine hundred eighteen thousand, nine hundred twenty-three".