12399 has 4 divisors (see below), whose sum is σ = 16536.
Its totient is φ = 8264.
The previous prime is 12391. The next prime is 12401. The reversal of 12399 is 99321.
It can be divided in two parts, 123 and 99, that added together give a palindrome (222).
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: 99321 = 3 ⋅33107.
It is a cyclic number.
It is not a de Polignac number, because 12399 - 23 = 12391 is a prime.
It is a D-number.
12399 is a lucky number.
It is a plaindrome in base 10.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (12391) 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, 2064 + ... + 2069.
It is an arithmetic number, because the mean of its divisors is an integer number (4134).
212399 is an apocalyptic number.
12399 is a deficient number, since it is larger than the sum of its proper divisors (4137).
12399 is an equidigital number, since it uses as much as digits as its factorization.
12399 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 4136.
The product of its digits is 486, while the sum is 24.
The square root of 12399 is about 111.3507970335.
The cubic root of 12399 is about 23.1452683272.
The spelling of 12399 in words is "twelve thousand, three hundred ninety-nine".