665923 has 2 divisors, whose sum is σ = 665924. Its totient is φ = 665922.

The previous prime is 665921. The next prime is 665947. The reversal of 665923 is 329566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665923 - 2¹ = 665921 is a prime.

Together with 665921, it forms a pair of twin primes.

It is a d-powerful number, because it can be written as 6 + 6² + 9⁶ + 5⁵ + 2¹⁷ + 3⁵ .

It is not a weakly prime, because it can be changed into another prime (665921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332961 + 332962.

It is an arithmetic number, because the mean of its divisors is an integer number (332962).

2⁶⁶⁵⁹²³ is an apocalyptic number.

665923 is a deficient number, since it is larger than the sum of its proper divisors (1).

665923 is an equidigital number, since it uses as much as digits as its factorization.

665923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 31.

The square root of 665923 is about 816.0410528889. The cubic root of 665923 is about 87.3255517544.

The spelling of 665923 in words is "six hundred sixty-five thousand, nine hundred twenty-three".