2. Multiply each bit by its corresponding power of 2 and add all the terms up.
1001 1001 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001(2) =
(1 × 251 + 0 × 250 + 0 × 249 + 1 × 248 + 1 × 247 + 0 × 246 + 0 × 245 + 1 × 244 + 0 × 243 + 0 × 242 + 0 × 241 + 0 × 240 + 0 × 239 + 0 × 238 + 0 × 237 + 0 × 236 + 0 × 235 + 0 × 234 + 0 × 233 + 0 × 232 + 0 × 231 + 0 × 230 + 0 × 229 + 0 × 228 + 0 × 227 + 0 × 226 + 0 × 225 + 0 × 224 + 0 × 223 + 0 × 222 + 0 × 221 + 0 × 220 + 0 × 219 + 0 × 218 + 0 × 217 + 0 × 216 + 0 × 215 + 0 × 214 + 0 × 213 + 0 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 0 × 26 + 0 × 25 + 0 × 24 + 0 × 23 + 0 × 22 + 0 × 21 + 1 × 20)(10) =
(2 251 799 813 685 248 + 0 + 0 + 281 474 976 710 656 + 140 737 488 355 328 + 0 + 0 + 17 592 186 044 416 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 1)(10) =
(2 251 799 813 685 248 + 281 474 976 710 656 + 140 737 488 355 328 + 17 592 186 044 416 + 1)(10) =
2 691 604 464 795 649(10)
The number 1001 1001 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001(2) converted from an unsigned binary (in base 2) and written as a positive integer (with no sign) in decimal system (in base ten):
1001 1001 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001(2) = 2 691 604 464 795 649(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.