947

947 is a prime number. The difference between any two of its digits is also a prime.

947 is a Chen prime because 947 + 2 = 949 = 13 x 73, so 949 is a semiprime.

947 is the maximum number of regions into which 43 lines divide the plane.

947 is the sum of seven consecutive primes: 947 = 113 + 127 + 131 + 137 + 139 + 149 + 151.

947 is the telephone area code for Oakland, Michigan. Note that the words "telephone code Oakland" have, respectively, 9, 4, and 7 digits.

Source: Prime Curios!

557

557 is a prime number.

557 is a Chen prime. A prime number p is called a Chen prime if p + 2 is either a prime or a product of two primes: (557 + 2 = 559 = 13 x 43). Chen primes are named after Jing Run Chen, who proved in 1966 that there are infinitely many such primes.

557 has a representation as a sum of two squares: 557 = 14² + 19².

557 is the hypotenuse of a primitive Pythagorean triple: 557² = 165² + 532².

USS Johnston (DD-557) was a World War II destroyer in the service of the U.S. Navy.

Source: Wikipedia