The public address you provided, "1FwZXt6EpRT7Fkndzv6K4b4DFoT4trbMrV", is a Bitcoin address. Bitcoin addresses are typically encoded in Base58 format, which is not directly convertible to a decimal number.
If you want to convert a Bitcoin address to a decimal number, you need to first decode the Base58 format to obtain the raw binary data, and then encode that to decimal.
However, I can’t perform the conversion directly here. You can use


