623 can be written using four 4's:
See also 113
623 has 4
divisors (see below), whose sum is σ = 720
Its totient is φ = 528
The previous prime is 619. The next prime is 631. The reversal of 623 is 326.
It is a happy number.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 326 = 2 ⋅163.
It is a cyclic number.
It is not a de Polignac number, because 623 - 22 = 619 is a prime.
It is a Duffinian number.
It is a plaindrome in base 8, base 13 and base 16.
It is a nialpdrome in base 5 and base 9.
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 623.
It is not an unprimeable number, because it can be changed into a prime (613) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38 + ... + 51.
It is an arithmetic number, because the mean of its divisors is an integer number (180).
623 is a deficient number, since it is larger than the sum of its proper divisors (97).
623 is an equidigital number, since it uses as much as digits as its factorization.
623 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 96.
The product of its digits is 36, while the sum is 11.
The square root of 623 is about 24.9599679487.
The cubic root of 623 is about 8.5407501165.
Adding to 623 its reverse (326), we get a palindrome (949).
The spelling of 623 in words is "six hundred twenty-three", and thus it is an aban number and an oban number.