This number is a prime.
The largest prime which cannot be represented with less than 37 5th powers.
The sums of the nth powers of its digits are prime for all n between 1 and 6 inclusive: sum of digits = 7, sum of squares of digits = 17, sum of cubes of digits = 43, sum of fourth powers = 113, sum of fifth powers = 307 and sum of sixth powers = 857. [Trotter]
Prime in the decimal expansion of square root of 5. [Haga]
The sum of the digits of first primes up to 223 is 449. Note the prime digits and their squares. [Silva]
The smallest prime showing a repeated prime digit. [Silva]
The largest gear in the Antikythera mechanism most likely had 223 teeth in connection with the prediction of lunar eclipses. [Beedassy]
The smallest prime formed from three prime digits. [Silva]
223 = -01+23+45+67+89. [Silva]
The smallest prime that has more primitive roots below p/2 than above p/2. [Gudipati]
"The children of Hashum, two hundred twenty and three." (Ezra 2:19, KJV) [Dorton]
(223, 227, 229, 233) is the first tetrad of successive primes whose the digits of each prime are complementary of the digits of another tetrad of successive primes, i.e., (887, 883, 881, 877). [Loungrides]
The only 3-digit isolated prime concatenated from two isolated primes, 2 and 23. [Loungrides]
ß was encoded by ECMA at position 223 (hexadecimal DF). [Hess]
223 is the first of 13 consecutive primes squared having squares as the last three digits. [Bergot]
The starting prime of a sequence of five primes following this rule: The Kth prime is obtained from the previous one substituting each digit d by d^K: 223, 449, 6464729, 129625612962562401166561, 1325904977763231257776132590497776323125777632102401177767776312577761. [Rivera]