161
Port 161 carries SNMP, the protocol used to monitor network equipment.
- Odd
- Composite
Where 161 fits
Why 161 is special
Almost every switch, router and printer reports its status over SNMP. Older versions authenticate with a plain-text community string that defaults to 'public', which is why an exposed 161 has long been one of the easiest ways to map an organisation's internal network from outside.
161 is part of
Factors & digit properties
- Divisors (4)
- 1, 7, 23, 161
- Prime factorisation
- 7 × 23
- Digit sum
- 8
- Digital root
- 8
Representations
- Decimal
- 161
- Binary
- 10100001
- Octal
- 241
- Hexadecimal
- a1
- Roman numeral
- CLXI
- Scientific notation
- 1.610 × 10^2
Other mathematical patterns
- Palindromic number
- Deficient number
- Semiprime
Related numbers & connections
SNMP polled and SNMP pushed. The polling interval on 161 is how long a fault can remain unnoticed, which is the entire argument for traps on 162.
View 162 →Technology & computing
SNMP v1 and v2c authenticate with a plain-text string, and the default is 'public'. An exposed port 161 has therefore been one of the simplest routes to a map of an organisation's internal equipment, which is why v3 exists and why so much kit still does not use it.
DocumentedTechnology & computing
Common questions
Is 161 a prime number?
No, 161 is not prime.
What are the factors of 161?
The factors of 161 are 1, 7, 23, 161.
What is 161 in Roman numerals?
161 in Roman numerals is CLXI.
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