669623 has 4 divisors (see below), whose sum is σ = 672288. Its totient is φ = 666960.

The previous prime is 669611. The next prime is 669637. The reversal of 669623 is 326966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 326966 = 2 ⋅163483.

It is a cyclic number.

It is not a de Polignac number, because 669623 - 2⁴ = 669607 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 669623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 911 + ... + 1472.

It is an arithmetic number, because the mean of its divisors is an integer number (168072).

2⁶⁶⁹⁶²³ is an apocalyptic number.

669623 is a deficient number, since it is larger than the sum of its proper divisors (2665).

669623 is a wasteful number, since it uses less digits than its factorization.

669623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2664.

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

The square root of 669623 is about 818.3049553803. The cubic root of 669623 is about 87.4869858196.

The spelling of 669623 in words is "six hundred sixty-nine thousand, six hundred twenty-three".