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
Fourth Battle of the Isonzo Fourth Battle of the Isonzo The Fourth Battle of the Isonzo was fought between the armies of Kingdom of Italy and those of Austria-Hungary on the Italian Front in World War I, between November 10 and December 2, 1915. In contrast to the previous three Battles of the Isonzo (June, July and October), this offensive lasted a short amount of time, and is sometimes considered a continuation of the previous offensive. Most of the clash was concentrated in the direction of Gorizia and on the Kras Plateau, though the push was distributed on the whole Isonzo front. The Italian Second