83

83 is a prime number. It is a Sophie Germain prime because 2 x 83 + 1 = 167, a prime.

83 is the smallest multidigit prime that consists of only curved digits.

83 is the only prime equal to the sum of the squares of the odd prime digits: 83 = 3² + 5² + 7².

83 is the smallest prime number that is the sum of a prime number of consecutive primes in a prime number of different ways: 83 = 23 + 29 + 31 = 11 + 13 + 17 + 19 + 23.


Bismuth, with atomic number 83, is the heaviest stable element.

Source: Prime Curios!