10000

This number is a composite.

The first known prime triplet with more than 10000 bits is 813529138*1939938^500 {-1, +1, +5}. [Luhn]

10000+9000+8000+7000+6000+5000+4000+3000+2000+1000 plus 1 is prime. [Silva]

10000 minus 2468 (the concatenation of the four single-digit even numbers in ascending order) is the four single-digit prime numbers in descending order. [Homewood]

The term gigantic prime (a prime number with at least 10,000 decimal digits) was coined by Samuel D. Yates.

10000 plus 123456789 is prime. [Silva]

The First 10,000 Primes.

2^9999 + 244164046679793 is the base prime for the smallest 10000-bit prime quadruplet. [Luhn]

The number of primes up to 10,000,000,000,000 having a final digit of 1 is divisible by 10,000. [Keith]