Numberwise

6891

RFC 6891 defines extension mechanisms for DNS.

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Where 6891 fits

Where 6891 fits: Mathematics, Technology, Related numbersMathematics: Semiprime, Lucky number (mathematical sieve). Technology: Numbers that make the internet work. Related numbers: 4033, 7871.MathematicsSemiprimeLucky number (mathematical …TechnologyNumbers that make the inter…Related numbers403378716891
6891 connects to 3 worlds: mathematics, technology, related numbers.

Why 6891 is special

It raised the DNS message size beyond 512 bytes, which DNSSEC required and which also made DNS a powerful amplifier for denial of service.

6891 is part of

Internet and web numbersNumbers around us

Factors & digit properties

Divisors (4)
1, 3, 2297, 6891
Prime factorisation
3 × 2297
Digit sum
24
Digital root
6

Representations

Decimal
6891
Scientific notation
6.891 × 10^3

Roman numerals

Roman numerals as modelled here goes up to 3,999.

Binary

1 1 0 1 0 1 1 1 0 1 0 1 1

1 × 4,096 + 1 × 2,048 + 0 × 1,024 + 1 × 512 + 0 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 6,891

Octal

1 5 3 5 3

1 × 4,096 + 5 × 512 + 3 × 64 + 5 × 8 + 3 × 1 = 6,891

Hexadecimal

1 a e b

1 × 4,096 + a × 256 + e × 16 + b × 1 = 6,891

Read as powers of two: 4,096 + 2,048 + 512 + 128 + 64 + 32 + 8 + 2 + 1 = 6,891.

In historical numeral systems

Egyptian

6 lotuses, 8 coils of rope, 9 hobbles, 1 stroke

6 × 1,000 + 8 × 100 + 9 × 10 + 1 × 1 = 6,891. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.

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

Related numbers & connections

Documented appearance
Larger DNS responses made DNSSEC possible and made open resolvers effective amplifiers.

Larger DNS responses made DNSSEC possible and made open resolvers effective amplifiers.

Connection
DNSSEC requires responses larger than the original 512-byte limit, which EDNS(0) provides and amplification attacks exploit.

DNSSEC requires responses larger than the original 512-byte limit, which EDNS(0) provides and amplification attacks exploit.

View 4033 →

Numbers Around Us

  • appears inNumbers that make the internet work
    why?

    Strength 0.50, confidence "high".

Other connections

  • is associated with4033
    why?

    Strength 0.50, confidence "high".

  • is associated with7871
    why?

    Strength 0.50, confidence "high".

How is 6891 connected to another number? →

Technology & computing

  • RFC 6891 specifies EDNS(0), allowing UDP DNS responses larger than 512 bytes. The increased response size is also what makes open resolvers effective reflection amplifiers.

    DocumentedTechnology & computingGeography: International — IETFPeriod: 2013

Common questions

Is 6891 a prime number?

No, 6891 is not prime.

What are the factors of 6891?

The factors of 6891 are 1, 3, 2297, 6891.

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