400 (number) third perfect number, a number whose divisors add up to the actual number (1+2+4+8+16+31+62+124+248=496). 497 = 7 × 71, sum of five consecutive primes (89 + 97 + 101 + 103 + 107) 498 = 2 × 3 × 83, sphenic number, untouchable number, admirable number, abundant number A prime number, Chen prime 400 (number) 400 (four hundred) is the natural number following 399 and preceding 401. 400 is the square of 20. 400 is the sum of the powers of 7 from 0 to 3, thus making it a repdigit in base 7 (1111). A circle is divided into
Joe Root (Pennsylvania) Joe Root (Pennsylvania) Joseph Root (1860 – 29 October 1912) was a well-known hermit who lived in what is now Presque Isle State Park in Pennsylvania. Born in Erie, Pennsylvania, Root lived on Presque Isle without any modern conveniences. Root moved away from his childhood home to Presque Isle while still in his adolescent years. As one of the first permanent inhabitants to the peninsula (Presque Isle wasn't declared an official state park until 1921), he built a number of shacks in various parts of the peninsula to suit the particular activity of any given day. There was also a