429
429 is the HTTP status code Too Many Requests — the client is being rate limited.
- Odd
- Composite
Where 429 fits
Why 429 is special
429 is how an API says slow down without saying go away. It is normally paired with a Retry-After header telling the client exactly how long to wait, which turns a refusal into an instruction. Every public API of any size issues it, and handling it correctly — backing off rather than retrying immediately — is the difference between a well-behaved client and an accidental attack.
Not just a mathematical number
429is also used in ways where ordinary arithmetic doesn't apply — each listed below with what genuinely does and doesn't follow from it.
- Mathematical number
A genuine quantity — its mathematical properties (prime, square, factors, and so on) are real facts about it.
A genuine quantity that ordinary arithmetic applies to — it can be prime, even, a perfect square, added to another number meaningfully, and so on.
- Code
Also used as a code — HTTP status codes.
An assigned identifier from a fixed registry or standard — its digits don't represent an amount, and arithmetic on it is meaningless (HTTP status 404 + 1 is not a 'better' status; it's a different, unrelated code).
Factors & digit properties
- Divisors (8)
- 1, 3, 11, 13, 33, 39, 143, 429
- Prime factorisation
- 3 × 11 × 13
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 429
- Scientific notation
- 4.290 × 10^2
Roman numerals
C D X X I X
CDXXIX uses the subtractive pair IX: one before ten — ten minus one.
Binary
1 1 0 1 0 1 1 0 1
1 × 256 + 1 × 128 + 0 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 1 × 1 = 429
Octal
6 5 5
6 × 64 + 5 × 8 + 5 × 1 = 429
Hexadecimal
1 a d
1 × 256 + a × 16 + d × 1 = 429
Read as powers of two: 256 + 128 + 32 + 8 + 4 + 1 = 429.
In historical numeral systems
Egyptian
4 coils of rope, 2 hobbles, 9 strokes
4 × 100 + 2 × 10 + 9 × 1 = 429. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
7 vertical wedges (sixties place), 9 vertical wedges (units place)
7 × 60 + 9 = 429. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
upsilon, then kappa, then theta, marked as a numeral
upsilon-kappa-theta + keraia
upsilon + kappa + theta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then kaf, then tet
tav-kaf-tet
tav (400) + kaf (20) + tet (9) = 429, written in descending order.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Deficient number
- Lucky number (mathematical sieve)
Related numbers & connections
429 is rate limiting, normally paired with a Retry-After header.
Numbers Around Us
- appears inHTTP status codes
why?
Strength 0.50, confidence "high".
Technology & computing
429 is normally sent with a Retry-After header giving an exact wait, which turns a refusal into an instruction. A client that honours it backs off; one that retries immediately turns a rate limit into an outage. Handling 429 correctly is the main thing separating a well-behaved integration from an accidental attack.
DocumentedTechnology & computing
Common questions
Is 429 a prime number?
No, 429 is not prime.
What are the factors of 429?
The factors of 429 are 1, 3, 11, 13, 33, 39, 143, 429.
What is 429 in Roman numerals?
429 in Roman numerals is CDXXIX. IX is subtractive: one before ten — ten minus one. Written additively it would be CCCCXXVIIII, which Roman inscriptions used freely — the strict subtractive form is a later convention.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026