29
29 is a prime number, the atomic number of copper, and forms a twin-prime pair with 31.
- Odd
- Prime
Where 29 fits
Why 29 is special
29's mathematics (prime, twin with 31) coincides with its everyday claim to fame: it's the extra day added to February in a leap year.
Same number, different meanings
How 29 is understood across different contexts — never implying one meaning because of another.
- Mathematics
29's mathematics (prime, twin with 31) coincides with its everyday claim to fame: it's the extra day added to February in a leap year.
- Science
29 is the atomic number of copper.
- Everyday life
February has 29 days only in a leap year, which occurs roughly once every four years to keep the calendar aligned with Earth's orbital period.
29 is part of
Factors & digit properties
- Divisors (2)
- 1, 29
- Prime factorisation
- 29
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 29
- Binary
- 11101
- Octal
- 35
- Hexadecimal
- 1d
- Roman numeral
- XXIX
- Scientific notation
- 2.900 × 10^1
Other mathematical patterns
- Deficient number
- Lucas number
- Sophie Germain prime
- Twin prime
Related numbers & connections
29 is a factor of 87 (29 × 3 = 87).
View 87 →29 and 31 are twin primes — two primes exactly two apart.
View 31 →Science
29 is the atomic number of copper.
DocumentedScience
Everyday life
February has 29 days only in a leap year, which occurs roughly once every four years to keep the calendar aligned with Earth's orbital period.
DocumentedEveryday life
Common questions
Is 29 a prime number?
Yes, 29 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 29?
The factors of 29 are 1, 29.
What is 29 in Roman numerals?
29 in Roman numerals is XXIX.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026