How many terms of the series 1 + 3 + 5 + 7 +... amount to a sum equal to 12345678987654321?

How many terms are identical in the two APs 19, 21, 23,... up to 110 terms and 19, 22, 25, 28,... up to 75 terms?

For the following two (02) items:
Let ( 6 + 10 + 14 +... up to m terms) =( 1 + 3 + 5 + 7 +... up to n terms)
where m < 25 and n < 25

What is the relation between m and n?

For the following two (02) items:
Let ( 6 + 10 + 14 +... up to m terms) =( 1 + 3 + 5 + 7 +... up to n terms)
where m < 25 and n < 25

How many values of m are possible?