155 (number)

From Free net encyclopedia

---

Current revision

List of numbers -- Integers << 100 110 120 130 140 150 160 170 180 190 >>
Cardinal	One hundred [and] fifty-five
Ordinal	155th
Factorization	<math>5 \cdot 31</math>
Divisors	1, 5, 31, 155
Roman numeral	CLV
Binary	10011011
Hexadecimal	9B

155 (one hundred fifty-five or one hundred and fifty-five) is the natural number following 154 and preceding 156. It is a composite number.

If you add up all the primes between the least and greatest prime factors of 155, that is, 5 and 31, the result is 155. Template:OEIS

It follows from the Sylow theorems that every group of order 155 has a normal subgroup of order 31 (hence is not a simple group, and is in fact solvable, thus verifying the odd order theorem), but since <math>5 \mid (31 - 1)</math> such a group is not necessarily a direct product of cyclic groups. However, it is a semidirect product.

There are 155 primitive permutations of degree 81. Template:OEIS2C

155 is also:

• The year AD 155 or 155 BC.
• The maximum possible score in a single break in snooker, with a free ball at the start of the break (147 is the highest possible without a free ball).
• The designation of some spur routes of Interstate 55.
• Alfa Romeo 155, a model of car

Template:Number-stub

fr:155 (nombre) ko:155 sl:155 (število)