Self numbers and self primes

In 1949 the Indian mathematician D.R. Kaprekar discovered a class of numbers called self-numbers. A number N is said to be a self number if it cannot be written as m + the sum of digits of m for any m. To find out if a given number is a self number, the idea is […]


If my name was a number, is it perhaps a prime number?

My wife is reading a book at the moment: “The Curious Incident of the Dog in the Night-Time by Mark Haddon“ Sitting in our sofa, she read out aloud for me from one of the pages, something she knew I would enjoy: “If you see someone’s name and you give each letter a value from […]