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Unique Properties of 181

  • 181 is the smallest multi-digit palindromic prime with an odd number of digits, such that increasing the middle digit by 1 produces another prime
  • 181 is the smallest odd prime (and fifth in all) exponent of 2 dissecting the interval between successive primes: 2181 ± 165 are both prime with no intervening primes
  • 181 is the start of the first occurrence of two successive primes (181, 191) using no prime digits
  • 181 starts the first occurrence of two consecutive primes which are both multidigit palindromes: 181, 191
  • 181 is the smallest palindromic prime with digit sum 10
  • 181 is the smallest number n such that the binary complement of n is greater than the binary complement of n2
  • 181 is the smallest number that have more zeros in its binary representation compared to its square

Rare Properties of 181

Palindromic prime

Common Properties of 181