The cache can be found at N 50° 5A.BCD W 000° 5E.FGH where the four digit number ABCD and four digit number EFGH, when multiplied together, give the number 19095887.
Since both ABCD and EFGH are prime numbers, there is only one solution.
In number theory, the prime factors of a positive integer are the prime numbers that divide into that integer exactly, without leaving a remainder. The process of finding these numbers is called integer factorisation, or prime factorisation.
The prime factorisation of a positive integer is a list of the integer's prime factors, together with their multiplicity. The fundamental theorem of arithmetic says that every positive integer has a unique prime factorisation.
Determining the prime factors of any number is an example of a problem frequently used to ensure cryptographic security in encryption systems. If the two prime numbers are sufficiently large, factorisation can take an incredibly long time (many years). Don't worry, prime factorization of this number, won't take you anything like as long.
A successful solution of this puzzle will give you a checksum (all 15 digits) equal to 48