Spotlight is probably sending the query to Google hence the correct result.
No, Spotlight is able to calculate offline, too! By the way, Apple has been started partnering with Microsoft and Bing for searches years ago and quit partnership with google.
Maybe you're right.
Spotlight seems to round integers starting from 16 digits decimal numbers. That limitation is leading to scientific E notation rounded to 14 post decimal positions, while 15 would be needed for exact results. -> Try to calculate in Spotlight: 1000000000000000 + 1 (or more).
Calculator app seems to deal with integer a little different. Provided the scientific calculator is set to 15 post decimal positions, integers whose binary length is 53 bits or more, seem to round in a way that behave like bugs. -> Try to add 1 to 9007199254740992 or multiply or divide 9007199254740993 by 1.
Calculator app shows another strange behavior, if typing an integer like 999999999 in scientific calculator, then switching to programming calculator, then just switch back to scientific calculator and subtract 1.
If you check out these examples and consider that the OP's question refers to a much larger integer with 24 digits or 77 bits in binary notation, I'm not wondering about Calculator app being unable to output a precise scientific E notation of 1e23.
However, I think all this could be explained by floating-point arithmetic by some clever Apple or Intel tech staff. Could someone try to calculate this on an ARM driven iOS device? Meanwhile the rest of us is calculating just with smaller numbers or is running third-party calculators, but these might be features, not bugs.
