There are exactly 5,761,455 prime numbers below 100,000,000, the first being two, and the last 99,999,989.
There are 5,761,455 primes less than 100,000,000. The largest of which is 99,999,989.
10
Infinate
The only consecutive primes between 1 and 100 are 2 and 3.
Ten of them.
One pair of twin primes between 135 and 145
One of them.
25 of them.
There are 57 such numbers.
There are five of them, including the number 1.
There are four pairs of twin primes between 2 and 35: (5,7) (11,13) (17,19) (29,31).
All pairs of two primes are coprime. There are fifteen primes under 50. So that means there are 105 unique pairs of "coprime primes", or more generally, pairs of primes, under 50.