This number is a prime.
The smallest prime (emirp) whose the sum and the product of digits are equal to the same powers of consecutive primes (16=2^4, 81=3^4). Note that the sum plus the product of these digits is equal to the largest double-digit prime (emirp). [Loungrides]
The only year of the 20th century to divide a repunit prime with no more than 21 digits: 111111111111111111111 = 3 * 37 * 43 * 239 * 1933 * 4649 * 10838689. It therefore divides the repunit prime with 2*21 = 42 digits. [Post]
Inauguration Day in the United States occurred on March 4 from 1798 up to the emirp year 1933 when Franklin D. Roosevelt was inaugurated President. Since then Inauguration Day has been on January 20. Furthermore, 3041933 (3/04/1933) is prime. [Green]
1933 = (19 + 28 + 37 + 46 + 55)/5. [Wesolowski]
The smallest happy balanced prime. [Gaydos]
The smallest prime obtained by concatenating all (unordered) pairs whose product is a given number (9 in this case): 1•9=3•3. [Leonardis]