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
Ontario Highway 401 runs parallel to the former Highway 2 along the shore of the Saint Lawrence River within the Saint Lawrence Valley. Northeast of Brockville is the interchange with Highway 416, which heads north to Ottawa. At the Ontario–Quebec border, Highway 401 becomes Autoroute 20 and continues to Montreal. The MTO publishes yearly traffic volume data for provincial highways, expressed as an average daily vehicle count over the span of a year (AADT). The table below compares the AADT at several locations along Highway 401 using data from 1969, 1988, 2008 and 2016. Highway 401's history predates its designation by over two