For less than the price of an exercise booklet, keep this website updated
21121is an odd number,as it is not divisible by 2
The factors for 21121 are all the numbers between -21121 and 21121 , which divide 21121 without leaving any remainder. Since 21121 divided by -21121 is an integer, -21121 is a factor of 21121 .
Since 21121 divided by -21121 is a whole number, -21121 is a factor of 21121
Since 21121 divided by -1 is a whole number, -1 is a factor of 21121
Since 21121 divided by 1 is a whole number, 1 is a factor of 21121
Multiples of 21121 are all integers divisible by 21121 , i.e. the remainder of the full division by 21121 is zero. There are infinite multiples of 21121. The smallest multiples of 21121 are:
0 : in fact, 0 is divisible by any integer, so it is also a multiple of 21121 since 0 × 21121 = 0
21121 : in fact, 21121 is a multiple of itself, since 21121 is divisible by 21121 (it was 21121 / 21121 = 1, so the rest of this division is zero)
42242: in fact, 42242 = 21121 × 2
63363: in fact, 63363 = 21121 × 3
84484: in fact, 84484 = 21121 × 4
105605: in fact, 105605 = 21121 × 5
etc.
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 21121, the answer is: yes, 21121 is a prime number because it only has two different divisors: 1 and itself (21121).
To know the primality of an integer, we can use several algorithms. The most naive is to try all divisors below the number you want to know if it is prime (in our case 21121). We can already eliminate even numbers bigger than 2 (then 4 , 6 , 8 ...). Besides, we can stop at the square root of the number in question (here 145.331 ). Historically, the Eratosthenes screen (which dates back to Antiquity) uses this technique relatively effectively.
More modern techniques include the Atkin screen, probabilistic tests, or the cyclotomic test.
Previous Numbers: ... 21119, 21120
Next Numbers: 21122, 21123 ...
Previous prime number: 21107
Next prime number: 21139