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Delbarhet

Delbarhet, or divisibility, is a relation between integers that describes when one number evenly divides another. For integers a and b with b not equal to zero, we say that b divides a if there exists an integer k such that a = b times k. In this case, b is called a divisor of a and a is a multiple of b. The relation is written with the symbol and notation b | a.

Examples illustrate the idea. Since 12 = 3 × 4, we have 3 | 12. Also 36 = 6

Delbarhet has several basic properties. It is transitive: if a | b and b | c, then a |

×
6,
so
6
|
36.
Conversely,
14
is
not
divisible
by
5,
so
5
∤
14.
A
key
special
case
concerns
zero:
for
any
nonzero
b,
b
divides
0
because
0
=
b
×
0.
However,
0
does
not
divide
any
nonzero
number,
and
many
sources
treat
0
|
0
as
undefined.
c.
It
is
reflexive
for
nonzero
numbers:
a
|
a
holds
for
any
a
≠
0.
Divisibility
also
relates
to
other
notions
such
as
divisors,
multiples,
prime
numbers,
and
the
greatest
common
divisor,
which
is
the
largest
positive
integer
that
divides
two
given
integers.
In
practice,
delbarhet
underpins
factorization,
modular
arithmetic,
and
various
algorithms
in
number
theory.