## Problem of the Week 1240## Nondivisibility by 11The number 545 has the curious property that upon replacing the digit in any single position by an arbitrary digit (from 0 to 9; it can be a leading 0 or just the same digit), the result is not divisible by 11. Is there a positive integer with this property having an even number of digits? Source: Sid Hollander, who found the ambiguity. |

27 July 2017