408
408 is the HTTP status code Request Timeout — the server gave up waiting for the client to finish.
- Even
- Composite
Where 408 fits
Why 408 is special
408 is the server's side of a stalled conversation. It fires when a client opens a connection and then sends too slowly, which is also how one class of denial-of-service attack works: hold thousands of connections open, sending a byte at a time. Timeouts exist as much for defence as for tidiness.
Not just a mathematical number
408is 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 (16)
- 1, 2, 3, 4, 6, 8, 12, 17, 24, 34, 51, 68, 102, 136, 204, 408
- Prime factorisation
- 2^3 × 3 × 17
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 408
- Scientific notation
- 4.080 × 10^2
Roman numerals
C D V I I I
CDVIII uses the subtractive pair CD: a hundred before five hundred — five hundred minus a hundred.
Binary
1 1 0 0 1 1 0 0 0
1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 408
Octal
6 3 0
6 × 64 + 3 × 8 + 0 × 1 = 408
Hexadecimal
1 9 8
1 × 256 + 9 × 16 + 8 × 1 = 408
Read as powers of two: 256 + 128 + 16 + 8 = 408.
In historical numeral systems
Egyptian
4 coils of rope, 8 strokes
4 × 100 + 8 × 1 = 408. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
6 vertical wedges (sixties place), 4 corner wedges + 8 vertical wedges (units place)
6 × 60 + 48 = 408. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
upsilon, then eta, marked as a numeral
upsilon-eta + keraia
upsilon + eta 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 het
tav-het
tav (400) + het (8) = 408, 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
- Abundant number
- Harshad (Niven) number
Related numbers & connections
408 fires when a client sends too slowly, which is also a recognised denial-of-service pattern.
Numbers Around Us
- appears inHTTP status codes
why?
Strength 0.50, confidence "high".
Technology & computing
408 exists partly for tidiness and partly for safety. Holding a connection open while sending data byte by byte is a recognised denial-of-service technique, because connections are a far scarcer resource than bandwidth; a request timeout is what stops a handful of slow clients from exhausting a server's capacity.
DocumentedTechnology & computing
Common questions
Is 408 a prime number?
No, 408 is not prime.
What are the factors of 408?
The factors of 408 are 1, 2, 3, 4, 6, 8, 12, 17, 24, 34, 51, 68, 102, 136, 204, 408.
What is 408 in Roman numerals?
408 in Roman numerals is CDVIII. CD is subtractive: a hundred before five hundred — five hundred minus a hundred. Written additively it would be CCCCVIII, 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