665423 has 4 divisors (see below), whose sum is σ = 725928. Its totient is φ = 604920.

The previous prime is 665419. The next prime is 665429. The reversal of 665423 is 324566.

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 665423 - 2² = 665419 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665392 and 665401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30236 + ... + 30257.

It is an arithmetic number, because the mean of its divisors is an integer number (181482).

2⁶⁶⁵⁴²³ is an apocalyptic number.

665423 is a deficient number, since it is larger than the sum of its proper divisors (60505).

665423 is a wasteful number, since it uses less digits than its factorization.

665423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60504.

The product of its digits is 4320, while the sum is 26.

The square root of 665423 is about 815.7346382250. The cubic root of 665423 is about 87.3036905140.

Adding to 665423 its reverse (324566), we get a palindrome (989989).

The spelling of 665423 in words is "six hundred sixty-five thousand, four hundred twenty-three".