odd, composite · 129th positive integer
The number 129
129 is an odd composite number. It is the 129th positive integer.
Quick reference
| Prime factorization | 3 × 43 |
| Divisors | 1, 3, 43, 129 |
| Binary | 10000001 |
| Hexadecimal | 0x81 |
| Roman numeral | CXXIX |
| Digit sum | 12 |
| Properties | odd, composite |
Reading 129 in NumGrid context
The 129 record above pulls directly from classical number theory plus NumGrid solver-derived puzzle statistics. What follows is the per-entity context — how 129 sits in the broader integer properties and number-guessing puzzles distribution and which underlying factors drive the headline numbers.
Every number on this page links back to classical number theory plus NumGrid solver-derived puzzle statistics; the methodology page describes the inputs, refresh cadence, and known limitations of the underlying data product.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for 129’s peers within positive integers within the NumGrid target pool. A single-entity reading without peer context can be misleading when an entity is an outlier on one axis but typical on another.
Frequently asked
Is 129 a prime number?
No. 129 is composite. Its prime factorization is 3 × 43.
What are the factors of 129?
The factors (divisors) of 129 are 1, 3, 43, 129.
What is 129 in binary?
129 in binary is 10000001. In hexadecimal it's 81.
What is 129 as a Roman numeral?
129 in Roman numerals is CXXIX.
What's the digit sum of 129?
Adding the digits of 129: 1 + 2 + 9 = 12.