2104
RFC 2104 defines HMAC.
- Even
- Composite
Where 2104 fits
Why 2104 is special
It exists because the obvious way to authenticate a message with a hash — prepending a key — is broken by length extension, and HMAC's nested construction is not.
Factors & digit properties
- Divisors (8)
- 1, 2, 4, 8, 263, 526, 1052, 2104
- Prime factorisation
- 2^3 × 263
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 2104
- Scientific notation
- 2.104 × 10^3
Roman numerals
M M C I V
MMCIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 0 0 0 0 0 1 1 1 0 0 0
1 × 2,048 + 0 × 1,024 + 0 × 512 + 0 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 2,104
Octal
4 0 7 0
4 × 512 + 0 × 64 + 7 × 8 + 0 × 1 = 2,104
Hexadecimal
8 3 8
8 × 256 + 3 × 16 + 8 × 1 = 2,104
Read as powers of two: 2,048 + 32 + 16 + 8 = 2,104.
In historical numeral systems
Egyptian
2 lotuses, 1 coil of rope, 4 strokes
2 × 1,000 + 1 × 100 + 4 × 1 = 2,104. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 5 vertical wedges (sixties place), 4 vertical wedges (units place)
35 × 60 + 4 = 2104. Places are separated by a space on the tablet, with the higher place written first.
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
Related numbers & connections
HMAC exists because prepending a key to a hash is broken by length extension, which affects MD5 and SHA-1 alike.
View 1321 →Technology & computing
RFC 2104 specifies keyed-hash message authentication using nested inner and outer hashing. The construction resists length extension attacks that affect naive keyed hashing over Merkle-Damgard functions.
DocumentedTechnology & computingGeography: International — IETFPeriod: 1997
Common questions
Is 2104 a prime number?
No, 2104 is not prime.
What are the factors of 2104?
The factors of 2104 are 1, 2, 4, 8, 263, 526, 1052, 2104.
What is 2104 in Roman numerals?
2104 in Roman numerals is MMCIV. IV is subtractive: one before five — five minus one. Written additively it would be MMCIIII, 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