500 = 22 x 53.
500 has two representations as a sum of two squares: 500 = 42 + 222 = 102 + 202.
There are exactly 500 prime numbers between 20,000 and 25,000.
166,500,333 = 1663 + 5003 + 3333.
500 is 4000 in base 5. It is 13310 in base 3 and 1313 in base 7.
Source: Numeropedia