Remarkably, it's almost prime: 3522942322 = 2 × 1761471161 (that's a 10-digit prime, by the way). Someone in my feed (in the UK) had a 12-digit prime phone number, but aside from that my office ...

An example of a prime number is 13 as it only has two factors: 13 and 1, whereas 9 is not a prime number as it has three factors: 9, 3 and 1. The first 10 prime numbers are: 2, 3, 5, 7, 11, 13, 17 ...

Save guides, add subjects and pick up where you left off with your BBC account. There are many methods to find the prime factors of a number, but one of the most common is to use a prime factor ...