123 (one hundred [and] twenty-three) is the natural number following 122 and preceding 124.
In mathematics
- 123 is a Lucas number.
- Along with 6, 123 is one of only two positive integers that is simultaneously two more than a perfect square and two less than a perfect cube (123 = 11<sup>2</sup> + 2 = 5<sup>3</sup> - 2).
In religion
In numerology, the sequence of 123 is associated with progress and the Holy Trinity, so it may be referred to as the Trinity of Progress or Triad of Progress.