2101 is a number n such that n, n + 1, and n + 2 are each the product of two primes: 2101 = 11 x 191, 2102 = 2 x 1051, 2103 = 3 x 701.
2101 is a number that yields a prime whenever a 1 is inserted anywhere in them, including the beginning or the end: 12101, 21101, and 21011 are all primes.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmcQDOQN31dSARYHlBf5fpLkr-1x4Rm2X_YhyphenhyphenGKva1rB3LoypoIobIZWm47W7AGqKHdYZLS7Cm9m6Uz_RqOliUN_kLxN1SxOPDNOobEAJ5myTI0PD0sGt_HEHXBvelzwWKN01uOX9anco/s400/n2101.jpg)
2101 Adonis was one of the first near-Earth asteroids to be discovered.
Source: On-Line Encyclopedia of Integer Sequences
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmcQDOQN31dSARYHlBf5fpLkr-1x4Rm2X_YhyphenhyphenGKva1rB3LoypoIobIZWm47W7AGqKHdYZLS7Cm9m6Uz_RqOliUN_kLxN1SxOPDNOobEAJ5myTI0PD0sGt_HEHXBvelzwWKN01uOX9anco/s400/n2101.jpg)
2101 Adonis was one of the first near-Earth asteroids to be discovered.
Source: On-Line Encyclopedia of Integer Sequences