Four thousand (4000) is the natural number following 3999 and preceding 4001. It is a decagonal number.
Selected numbers in the range 4001-4999
- 4005 - triangular number
- 4007 - safe prime
- 4010 - magic constant of n×n magic square and n-Queens Problem for n = 20.
- 4019 - Sophie Germain prime
- 4028 - sum of the first 45 primes
- 4030 - 3rd weird number
- 4031 - sum of the cubes of the first six primes
- 4033 - 6th super-Poulet number
- 4060 - tetrahedral number
- 4073 - Sophie Germain prime
- 4079 - safe prime
- 4095 - triangular number
- 4096 - 12th power of two, 16th cube, 64^2
- 4104 = 2^3 + 16^3 = 9^3 + 15^3
- 4127 - safe prime
- 4139 - safe prime
- 4166 - centered heptagonal number
- 4181 - Fibonacci number
- 4186 - triangular number
- 4199 - highly cototient number
- 4200 - nonagonal number, pentagonal pyramidal number
- 4210 - 11th semi-meandric number
- 4211 - Sophie Germain prime
- 4219 - cuban prime of the form x = y + 1
- 4225 = 65^2, centered octagonal number
- 4227 - sum of the first 46 primes
- 4257 - decagonal number
- 4259 - safe prime
- 4271 - Sophie Germain prime
- 4278 - triangular number
- 4283 - safe prime
- 4289 - highly cototient number
- 4324 - 23rd square pyramidal number
- 4349 - Sophie Germain prime
- 4356 - sum of the cubes of the first eleven integers, 66^2
- 4369 - 7th super-Poulet number
- 4371 - triangular number
- 4373 - Sophie Germain prime
- 4391 - Sophie Germain prime
- 4400 - the number of missing persons in the sci-fi show The 4400
- 4409 - Sophie Germain prime, highly cototient number
- 4411 - centered heptagonal number
- 4438 - sum of the first 47 primes
- 4446 - nonagonal number
- 4447 - cuban prime of the form x = y + 1
- 4465 - triangular number
- 4481 - Sophie Germain prime
- 4489 = 67^2, centered octagonal number
- 4495 - tetrahedral number
- 4503 - largest number not the sum of four or fewer squares of composites
- 4505 - 5th Zeisel number
- 4522 - decagonal number
- 4547 - safe prime
- 4560 - triangular number
- 4579 - octahedral number
- 4607 - Woodall number
- 4619 - highly cototient number
- 4624 = 68^2
- 4641 - magic constant of n×n magic square and n-Queens Problem for n = 21.
- 4656 - triangular number
- 4661 - sum of the first 48 primes
- 4663 - centered heptagonal number
- 4679 - safe prime
- 4681 - 8th super-Poulet number
- 4699 - nonagonal number
- 4703 - safe prime
- 4705 = 48² + 49² = 17² + 18² + ... 26²
- 4727 - sum of the squares of the first twelve primes
- 4733 - Sophie Germain prime
- 4753 - triangular number
- 4761 = 69^2, centered octagonal number
- 4787 - safe prime
- 4788 - 14th Keith number
- 4793 - Sophie Germain prime
- 4795 - decagonal number
- 4799 - safe prime
- 4801 - cuban prime of the form x = y + 2
- 4851 - triangular number, pentagonal pyramidal number
- 4871 - Sophie Germain prime
- 4879 - 11th Kaprekar number
- 4888 - sum of the first 49 primes
- 4900 - the only square-pyramidal square other than 1[1] (http://mathworld.wolfram.com/CannonballProblem.html), 70^2
- 4913 - 17th cube
- 4919 - Sophie Germain prime, safe prime
- 4922 - centered heptagonal number
- 4941 - centered cube number
- 4943 - Sophie Germain prime
- 4950 - triangular number, 12th Kaprekar number
- 4959 - nonagonal number
- 4960 - tetrahedral number; greater of 4th pair of Smith brothersko:4000
