2818
RFC 2818 defines HTTP over TLS.
- Even
- Composite
Where 2818 fits
Why 2818 is special
It specifies how a certificate is checked against the hostname requested, which is the step that makes the padlock mean anything. Skipping it is how man-in-the-middle attacks succeed against otherwise encrypted connections.
Same number, different meanings
How 2818 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It specifies how a certificate is checked against the hostname requested, which is the step that makes the padlock mean anything. Skipping it is how man-in-the-middle attacks succeed against otherwise encrypted connections.
- Technology & computing
RFC 2818 defines verifying that the certificate presented actually belongs to the site requested. Encryption without that check protects the channel to an attacker just as well as to the intended server.
- Science
NGC 2818 is a planetary nebula projected against an open cluster. Whether it is physically a member has been disputed, since a cluster old enough to produce it should have dispersed.
2818 is part of
Factors & digit properties
- Divisors (4)
- 1, 2, 1409, 2818
- Prime factorisation
- 2 × 1409
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 2818
- Binary
- 101100000010
- Octal
- 5402
- Hexadecimal
- b02
- Roman numeral
- MMDCCCXVIII
- Scientific notation
- 2.818 × 10^3
Other mathematical patterns
- Deficient number
- Happy number
- Semiprime
Related numbers & connections
HTTP over TLS is what the padlock refers to, and the certificate check is what makes it mean anything.
HSTS closes the plaintext window that HTTP over TLS otherwise leaves open on a first visit.
View 6797 →Technology & computing
RFC 2818 defines verifying that the certificate presented actually belongs to the site requested. Encryption without that check protects the channel to an attacker just as well as to the intended server.
DocumentedTechnology & computingPeriod: 2000
Science
NGC 2818 is a planetary nebula projected against an open cluster. Whether it is physically a member has been disputed, since a cluster old enough to produce it should have dispersed.
DocumentedSciencePeriod: 1826–
Common questions
Is 2818 a prime number?
No, 2818 is not prime.
What are the factors of 2818?
The factors of 2818 are 1, 2, 1409, 2818.
What is 2818 in Roman numerals?
2818 in Roman numerals is MMDCCCXVIII.
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: 3 August 2026