Your final answer will be a number (or maybe not?)
6.1482925535194332784626433, 15, 70, 5388440228181184467208035634811703511875, 45, 1207432478148385373947988/38313917, 15, 70, ?
This number appears to be the same as pi (truncated to 26 places), but with eight digits changed. That 26 is suspicious - looking at the changed digits, they're all between one and eight. Taking the nth letter, where n is the position of the digit changed to k, gives LEONHARD.
These numbers look like "IS TO".
This number prime factorizes as $3^6\cdot 5^4\cdot 7^8\cdot 11^7\cdot 47^3\cdot 71^1\cdot 73^5\cdot 83^2$. Those exponents range from 1 to 8, and the primes are pretty small. Sort by exponent, then take each prime's index in the list of primes (2 maps to A, 3 to B, 5 to C, 7 to D...), and you get TWO CUBED, which is naturally a clue for EIGHT.
45 looks like "AS" in a similar way to how 15 and 70 yielded IS and TO.
Dividing this out gives 31514200914210504.0825... . Taking pairs of digits and converting to letters gives "CONTINUED", a hint to look at the continued fraction. The continued fraction for this number is [31514200914210504; 12, 9, 11, 5, 2, 12, 15, 15], and converting those to letters gives "LIKE BLOO", a hint to the word IMAGINARY (a reference to Bloo from the cartoon Foster's Home for Imaginary Friends)
IS, TO again.
LEONHARD means Euler's number, e.
IMAGINARY means the imaginary unit, i. That means we have "e is to EIGHT as i is to ???", and the answer is INFINITY, another "number" starting with its corresponding letter.