1623 has 4 divisors (see below), whose sum is σ = 2168. Its totient is φ = 1080.

The previous prime is 1621. The next prime is 1627. The reversal of 1623 is 3261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3261 = 3 ⋅1087.

It is not a de Polignac number, because 1623 - 2¹ = 1621 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a nialpdrome in base 12 and base 15.

It is a junction number, because it is equal to n+sod(n) for n = 1599 and 1608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621) 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, 268 + ... + 273.

It is an arithmetic number, because the mean of its divisors is an integer number (542).

2¹⁶²³ is an apocalyptic number.

1623 is a deficient number, since it is larger than the sum of its proper divisors (545).

1623 is an equidigital number, since it uses as much as digits as its factorization.

1623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544.

The product of its digits is 36, while the sum is 12.

The square root of 1623 is about 40.2864741570. The cubic root of 1623 is about 11.7518482078.

Adding to 1623 its reverse (3261), we get a palindrome (4884).

The spelling of 1623 in words is "one thousand, six hundred twenty-three".