501

501 (five hundred [and] one) is the natural number following 500 and preceding 502. 501 is the sum of the first eighteen primes.There are 501 degree-8 polynomials with integer coefficients, all of whose roots are in the unit disk.There are 501 ways of partitioning the digits from 0 to 9 into two sets, each of which contains at least two digits, and 501 ways of partitioning a set of five elements into any number of ordered sequences. 501 is also a figurate number based on the 5-orthoplex or 5-dimensional cross polytope.