The decimal form of an IP address is a large integer without division into octets, that is, without periods in the record. To convert from normal form to decimal number, you must follow the algorithm:
The number from the first octet (leftmost) must be multiplied by 16777216 (256^3).
The number from the second octet must be multiplied by 65536 (256^2).
The number from the third octet must be multiplied by 256.
It is necessary to add up all the received numbers, as well as the fourth octet (formally, the fourth octet must be multiplied by 256^0, that is, by one).