primes by hand

[futurebird]

What is the fastest way to tell if a largish number is prime ***using only a a pencil and paper***?

Please find out if each of these is prime and explain the process you used.

a. 1,979

b. 3,127

c. 2,281

d. 42,499

e. 10,573

f. 847,313

g. 104,009