the magical number...

A number is $a_1a_2a_3a_4$ .

$a_1$ is the number of (100/100) numbers below 100.

$a_2$ is 100^ln(100-100)

$a_3$ is the number even primes.

$a_4$ is the number of prime numbers under the square root of 100.

The answer is not 100.