How many numbers can be rounded to 34 million to the nearest millions?

Answer 1

Infinitely many numbers.

1 million and 1 whole numbers . Although, technically 34 million, itself, would not be rounded. This would comprise the numbers from [33,500,000, 34,500,000]. In the first case the 5 is rounded up while in the second it is rounded down. This is consistent with the rule of "Round up or down so that the new last digit is even". This is the default rounding mode used in IEEE 754 computing functions and operators.

Answer 2

in whole numbers, 33,500,000 to 34,499,999