465
Port 465 carries SMTP over TLS for submitting mail.
- Odd
- Composite
Where 465 fits
Why 465 is special
465 was assigned for encrypted mail submission, deprecated in favour of STARTTLS on 587, and then reinstated in 2018 when implicit TLS proved the more reliable design. It is one of the clearer cases of a standards body reversing itself on evidence.
465 is part of
Factors & digit properties
- Divisors (8)
- 1, 3, 5, 15, 31, 93, 155, 465
- Prime factorisation
- 3 × 5 × 31
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 465
- Binary
- 111010001
- Octal
- 721
- Hexadecimal
- 1d1
- Roman numeral
- CDLXV
- Scientific notation
- 4.650 × 10^2
Other mathematical patterns
- Triangular number
- Deficient number
- Harshad (Niven) number
Related numbers & connections
Two routes to encrypted mail submission: implicit TLS on 465 and an upgrade from plaintext on 587. 465 was deprecated in favour of 587 and then reinstated in 2018, which is a rare reversal for a standards body.
View 587 →Other connections
- contrasts with587
why?
Strength 0.50, confidence "high".
Technology & computing
465 was assigned for implicit TLS mail submission, deprecated in favour of upgrading a plain connection on 587, then formally reinstated in 2018 when implicit TLS proved more reliable in practice. Standards rarely reverse this cleanly, which is what makes it worth recording.
DocumentedTechnology & computing
Common questions
Is 465 a prime number?
No, 465 is not prime.
What are the factors of 465?
The factors of 465 are 1, 3, 5, 15, 31, 93, 155, 465.
What is 465 in Roman numerals?
465 in Roman numerals is CDLXV.
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: 3 August 2026