161 (number)

In mathematics

• 161 is the sum of five consecutive prime numbers: 23, 29, 31, 37, and 41.
• 161 is a hexagonal pyramidal number.
• 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.
• is a commonly used rational approximation of the square root of 5 and is the closest fraction with denominator <300 to that number.

  In other fields

• 161 as a code for Anti-Fascist Action, sometimes used in ''161>88''