9000 (number)

ISO 9000 is the ISO's standard for Quality Management System in production environments. This includes ISO 9001–9004.
The BFG-9000 is the most powerful weapon in the video game series Doom

Selected numbers in the range 9000–9999

9009 – centered cube number
9025 – 95², centered octagonal number
9029 – Sophie Germain prime
9045 – triangular number
9059 – Sophie Germain prime
9072 – decagonal number
9077 – Markov number
9091 – unique prime
9126 – pentagonal pyramidal number
9139 – tetrahedral number
9180 – triangular number
9216 – 96²
9221 – Sophie Germain prime
9224 – octahedral number
9241 – cuban prime of the form x = y + 1
9261 - 21³, largest 4 digit perfect cube
9272 – weird number
9283 – centered heptagonal number
9293 – Sophie Germain prime
9316 – triangular number
9334 – nonagonal number
9349 – Lucas prime
9371 – Sophie Germain prime
9397 – balanced prime
9409 – 97², centered octagonal number
9419 – Sophie Germain prime
9453 – triangular number
9455 – square pyramidal number
9457 – decagonal number
9467 – safe prime
9473 – Sophie Germain prime, balanced prime
9479 – Sophie Germain prime
9539 – Sophie Germain prime
9587 – safe prime
9591 – triangular number
9604 – 98²
9629 – Sophie Germain prime
9647 – centered heptagonal number
9660 – ISO 9660 standard for CD-ROM file system
9689 – Sophie Germain prime
9699 – nonagonal number
9730 – triangular number
9743 – safe prime
9791 – Sophie Germain prime
9800 – member of a Ruth-Aaron pair (first definition) with 9801
9801 – 99², centered octagonal number, member of a Ruth-Aaron pair (first definition) with 9800
9839 – safe prime
9850 – decagonal number
9855 – magic constant of n × n normal magic square and n-Queens Problem for n = 27.
9870 – triangular number
9871 – balanced prime
9880 – tetrahedral number
9887 – safe prime
9899 – ISO 9899 standard for C programming language
9901 – unique prime
9923 – probably smallest certainly executable prime number on x86 MS-DOS
9999 – Kaprekar number, Repdigit