Semiprime Numbers Day - October 14
Happy Semiprime Numbers Day! Semiprime numbers are the product of exactly 2 prime numbers , so 4 (2 X 2) and 6 (2 X 3) are semiprimes, but 8 (2 X 2 X 2) and 30 (2 X 3 X 5) are not. More examples are here: Public key cryptography depends on the difficulty of factoring very large semiprime numbers for its effectiveness. Semiprime Numbers Day is celebrated on the date 10/14, or October 14, since 10 and 14 are the largest consecutive semiprime numbers forming a valid date.