Integer overflow for 64 bit platform
If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float.
This above general rule differs depending on whether a 32 bit or 64 bit platform is used, which is described as follows.
Platform:32 bit,Range: -2^31-1 to 2^31-1,Numbers:-2147483647 to 2147483647
Platform:64 bit,Range: -2^63-1 and 2^63 -1,Numbers:-9223372036854775807 to 9223372036854775807
$large_number = 9223372036854775808;