2. Multiply each bit by its corresponding power of 2 and add all the terms up.
101 0001 0100 0011 0000 0010 1101(2) =
(1 × 226 + 0 × 225 + 1 × 224 + 0 × 223 + 0 × 222 + 0 × 221 + 1 × 220 + 0 × 219 + 1 × 218 + 0 × 217 + 0 × 216 + 0 × 215 + 0 × 214 + 1 × 213 + 1 × 212 + 0 × 211 + 0 × 210 + 0 × 29 + 0 × 28 + 0 × 27 + 0 × 26 + 1 × 25 + 0 × 24 + 1 × 23 + 1 × 22 + 0 × 21 + 1 × 20)(10) =
(67 108 864 + 0 + 16 777 216 + 0 + 0 + 0 + 1 048 576 + 0 + 262 144 + 0 + 0 + 0 + 0 + 8 192 + 4 096 + 0 + 0 + 0 + 0 + 0 + 0 + 32 + 0 + 8 + 4 + 0 + 1)(10) =
(67 108 864 + 16 777 216 + 1 048 576 + 262 144 + 8 192 + 4 096 + 32 + 8 + 4 + 1)(10) =
85 209 133(10)
The number 101 0001 0100 0011 0000 0010 1101(2) converted from an unsigned binary (in base 2) and written as a positive integer (with no sign) in decimal system (in base ten):
101 0001 0100 0011 0000 0010 1101(2) = 85 209 133(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.