161 (number)

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
← 160 161 162 →
Cardinalone hundred sixty-one
Ordinal161st
(one hundred sixty-first)
Factorization7 × 23
Divisors1, 7, 23, 161
Greek numeralΡΞΑ´
Roman numeralCLXI
Binary101000012
Ternary122223
Octal2418
Duodecimal11512
HexadecimalA116

161 (one hundred [and] sixty-one) is the natural number following 160 and preceding 162.

In mathematics[edit]

  • 161 is the sum of five consecutive prime numbers: 23, 29, 31, 37, and 41
  • 161 is a hexagonal pyramidal number.[1]
  • 161 is a semiprime. Since its prime factors 7 and 23 are both Gaussian primes, 161 is a Blum integer.
  • 161 is a palindromic number[2]
  • 161/72 is a commonly used rational approximation of the square root of 5 and is the closest fraction with denominator <300 to that number.

In the military[edit]

In music[edit]

In transportation[edit]

In other fields[edit]

161 is also:

See also[edit]

External links[edit]

References[edit]

  1. ^ "Sloane's A002412 : Hexagonal pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.
  2. ^ "A002113 - Oeis".
  3. ^ "161>88". Czech Republic: Antifascist Action. 2012. Archived from the original (Documentary) on 3 January 2018. Retrieved 2 January 2018.