108123

108123 is a number that belongs to the set of natural numbers. It is not a prime number, as it can be divided by 1, 3, 9, 12, 27, 36, 108, 324, 1081, 3243, 9009, 10812, 36036, and 108123, among others. Its divisors include 1, 3, 9, 12, 27, 36, 108, 324, 1081, 3243, 9009, 10812, 36036, and 108123.

The number 108123 can be expressed as a sum of two squares in two different ways: 108123 = 324^2 + 0^2 and 108123 = 323^2 + 1^2. This property makes it a sum of two squares number.

In the context of combinatorics, 108123 is the sum of the first 324 natural numbers, as it can be calculated using the formula for the sum of an arithmetic series: S = n/2 * (first term + last term), where n is the number of terms. In this case, n = 324, the first term is 1, and the last term is 324.

108123 is also a happy number, meaning that by repeatedly replacing the number with the sum of the squares of its digits, it eventually reaches 1. The sequence for 108123 is: 108123 → 145 → 42 → 20 → 4 → 16 → 37 → 58 → 89 → 145, and it repeats from there.

The number 108123 appears in the OEIS (On-Line Encyclopedia of Integer Sequences) as sequence A005187, which lists numbers that are the sum of the first n natural numbers. It is also mentioned in the context of happy numbers in sequence A003294.