623309 has 4 divisors (see below), whose sum is σ = 632160. Its totient is φ = 614460.

The previous prime is 623303. The next prime is 623321. The reversal of 623309 is 903326.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 903326 = 2 ⋅451663.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-623309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 623309.

It is not an unprimeable number, because it can be changed into a prime (623303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4319 + ... + 4460.

It is an arithmetic number, because the mean of its divisors is an integer number (158040).

2⁶²³³⁰⁹ is an apocalyptic number.

It is an amenable number.

623309 is a deficient number, since it is larger than the sum of its proper divisors (8851).

623309 is an equidigital number, since it uses as much as digits as its factorization.

623309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8850.

The product of its (nonzero) digits is 972, while the sum is 23.

The square root of 623309 is about 789.4992083593. The cubic root of 623309 is about 85.4216191722.

Subtracting from 623309 its sum of digits (23), we obtain a triangular number (623286 = T₁₁₁₆).

The spelling of 623309 in words is "six hundred twenty-three thousand, three hundred nine".