121 (number)
121 is the natural number following 120 and preceding 122.In mathematics
One hundred twenty-one' is a square and is the sum of three consecutive primes. There are no squares besides 121 known to be of the form, where p is prime. Other such squares must have at least 35 digits.
There are only two other squares known to be of the form n! + 1, supporting Brocard's conjecture. Another example of 121 being of the few examples supporting a conjecture is that Fermat conjectured that 4 and 121 are the only perfect squares of the form x3 - 4.
It is also a star number and a centered octagonal number.
board has 121 holes
In base 10, it is a Smith number since its digits add up to the same value as its factorization and as a consequence of that it is a Friedman number. But it can not be expressed as the sum of any other number plus that number's digits, making 121 a self number.121 is also:
