155is an odd number,as it is not divisible by 2
The factors for 155 are all the numbers between -155 and 155 , which divide 155 without leaving any remainder. Since 155 divided by -155 is an integer, -155 is a factor of 155 .
Since 155 divided by -155 is a whole number, -155 is a factor of 155
Since 155 divided by -31 is a whole number, -31 is a factor of 155
Since 155 divided by -5 is a whole number, -5 is a factor of 155
Since 155 divided by -1 is a whole number, -1 is a factor of 155
Multiples of 155 are all integers divisible by 155 , i.e. the remainder of the full division by 155 is zero. There are infinite multiples of 155. The smallest multiples of 155 are:
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 155, the answer is: No, 155 is not a prime number.
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 155). 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 12.45 ). 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 prime number: 151
Next prime number: 157