An IPv4 address consists of 4 bytes and is generally represented as A.B.C.D - for example the IP address of mentalized.net is 217.116.224.24 (note, you can’t actually use this IP address to access mentalized.net). This address can also be expressed as the numerical value, 3648315416.
The numerical value is easily calculated by considering an IP address as being a 4 byte value. In hex this gives us D9.74.E0.18 - dots added for clarity. Without the dots, the hex value represented here (0xD974E018 - which can also be used as an IP address) equals 3648315416. In short:
217.116.224.24 = 0xD974E018 = 3648315416
There you go, Thomas :)