600 (six hundred) is the natural number following 599 and preceding 601. 

Six hundred is a composite number, an abundant number, a pronic number and a Harshad number. 

601 prime number, centered pentagonal number 602 = 2 × 7 × 43, nontotient, area code for Phoenix, AZ along with 480 and 623 603 = 3 × 67, Harshad number, area code for New Hampshire 604 = 2 × 151, nontotient, totient sum for first 44 integers, area code for southwestern British Columbia (Lower Mainland, Fraser Valley, Sunshine Coast and Sea to Sky) 605 = 5 × 11, Harshad number 606 = 2 × 3 × 101, sphenic number, sum of six consecutive primes (89 + 97 + 101 + 103 + 107 + 109) 607 prime number, sum of three consecutive primes (197 + 199 + 211), Mertens function(607) = 0, balanced prime, strictly non-palindromic number 608 = 2 × 19, Mertens function(608) = 0, nontotient, happy number 609 = 3 × 7 × 29, sphenic number 

610 = 2 × 5 × 61, sphenic number, nontotient, Fibonacci number, Markov number. Also a kind of telephone wall socket used in Australia. 611 = 13 × 47 612 = 2 × 3 × 17, Harshad number, area code for Minneapolis, MN 613 = Primes: prime number, first number of prime triple ("p", "p" + 4, "p" + 6), middle number of sexy prime triple ("p" − 6, "p", "p" + 6). Geometrical numbers: Centered square number with 18 per side, circular number of 21 with a square grid and 27 using a triangular grid. Also 17-gonal. Hypotenuse of a right triangle with integral sides, these being 35 and 612. Partitioning: 613 partitions of 47 into non-factor primes, 613 non-squashing partitions into distinct parts of the number 54. Squares: Sum of squares of two consecutive integers, 17 and 18. Additional properties: a lucky number.
What's an example of a Harshad number?
603 = 3 × 67, Harshad number