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
Bristol 401 with the then-unique door handle arrangement, is believed to give the 401 a drag coefficient of less than Cd 0.36 — competitive even by today's standards and remarkable for the time. The engine was the same 2-litre in-line six-cylinder petrol unit of the 400, but was upgraded through improved Solex carburettors to increase power by to , which improved the performance further beyond what was achieved by the aerodynamics. The suspension is independent at the front using a transverse leaf spring and wishbones and the rigid axle at the rear uses torsion bars. Steering is by rack and pinion. The