 Informally, the probability that any number is divisible by a prime (or in fact any integer) formula_3 is formula_4; for example, every 7th integer is divisible by 7.Hence the probability that two numbers are both divisible by "p" is formula_5, and the probability that at least one of them is not is formula_6.Any finite collection of divisibility events associated to distinct primes is mutually independent.