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posted ago by penisse ago by penisse +22 / -0
  • 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
  • 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.