500 (five hundred) is the natural number following 499 and preceding 501. 

500 is a Harshad number in bases 5, 6, 10, 11, 13, 15 and 16. 

Five hundred is also 



501 = 3 × 167. It is: 502 = 2 × 251, also a proposed HTTP status code for indicating server is temporarily overloaded, SMTP status code meaning command not implemented 503 is: 504 = 2 × 3 × 7. It is: 505 = 5 × 101, Harshad number in bases 3, 5 and 6 

This number is the magic constant of "n"×"n" normal magic square and "n"-queens problem for "n" = 10. 

New Mexico – Before October 7, 2007, The United States state of New Mexico had a single area code of 505. The state was, and still is, referred to as 'the 505' in slang. 506 = 2 × 11 × 23. It is: 507 = 3 × 13, Harshad number in bases 13 and 14. 508 = 2 × 127, sum of four consecutive primes (113 + 127 + 131 + 137), Harshad number in base 13. 509 is: 

510 = 2 × 3 × 5 × 17. It is: 511 = 7 × 73. It is: 512 = 2. It is: 513 = 3 × 19. It is: 514 = 2 × 257, it is: 515 = 5 × 103, it is: 516 = 2 × 3 × 43, it is: 517 = 11 × 47, it is: 518 = 2 × 7 × 37, it is: 519 = 3 × 173, it is:
what date did the area code change in NM
Before October 7, 2007, The United States state of New Mexico had a single area code of 505. 