Currently the "Number" type is used for every number and it gets stored as a double, and can "only" represent "integers" safely in the range of ±(2^53 -1). Though there is a "BigInt" [1] type.
[0] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data...
[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data...