If you like numbers, you'll like Sum of Primes. It's a cool little app that will display the sum of consecutive primes for integers greater than 1 up to 100, 000, 000. For example, the number 41 can be written as 2 + 3 + 5 + 7 + 11 + 13. However, there are some integers that cannot be expressed this way because their summands do not consist of consecutive primes.