What does it mean when my variable is always converted to 2147483647......?

I have the following code as my entity:

/**
 *
 * @Entity
 * @Table(name="group")
 *
 **/
Class Group {

/**
 *
 * @Column(type="string", nullable=true)
 **/
 private $phone;

(etc...)

__get( $var ) {
return $this->$var;
}
__set( $var, $val ){
 $this->$var = $val;
}

I then try to modify this with a number larger than nine digits. for example,

$group-开发者_JS百科>phone = 5147811326;

$phone is set to 2147483647. The same occurs with 1111111111 (it is conveted to 2147483647)

If I try 514781, it keeps the numbers fine. But over 9 digits it just converts. I originally had the mysql column as an integer but converted it to string...still a problem.

what is happening?!??!!

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The number "5147811326" cannot be stored in a 32-bit integer because there are simply not enough bits. The highest binary value of a 32-bit integer is "11111111 11111111 11111111 11111111" (or 2147483647 in the decimal system). Try eiter a 64-bit integer or a string to store the phone number.

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This means the data type you are using is 32 bits. 2147483647 is equal to 2³¹ − 1.