π(x) is used to represent the number of all prime numbers not exceeding x, and there is an approximate formula π(x)≈x/ln(x).

The exact value of π(x) can be calculated by mathematical software.

π( 10)=4

π( 100)=25

π( 1000)= 168

π( 10000)= 1229

π( 100000)=9592

π( 1000000)=78498

π( 10000000)=664579

π( 100000000)=576 1455

π( 1000000000)=50847534

The largest prime number in 100 million is 999989, and the closest prime number to 100 million is 100000007.