30001 to 30999

• 30029 = primorial prime
• 30030 = primorial^[1]
• 30031 = smallest composite number which is one more than a primorial
• 30203 = safe prime
• 30240 = harmonic divisor number^[2]
• 30323 = Sophie Germain prime and safe prime
• 30420 = pentagonal pyramidal number^[3]
• 30537 = Riordan number
• 30694 = open meandric number
• 30941 = first base 13 repunit prime

31000 to 31999

• 31116 = octahedral number^[4]
• 31337 = cousin prime, pronounced elite, an alternate way to spell 1337, an obfuscated alphabet made with numbers and punctuation, known and used in the gamer, hacker, and BBS cultures.
• 31395 = square pyramidal number
• 31397 = prime number followed by a record prime gap of 72, the first greater than 52^[5]
• 31688 = the number of years approximately equal to 1 trillion seconds
• 31721 = start of a prime quadruplet^[6]
• 31929 = Zeisel number^[7]

32000 to 32999

• 32043 = smallest number whose square is pandigital.
• 32045 = can be expressed as a sum of two squares in more ways than any smaller number.^[8]
• 32760 = harmonic divisor number^[2]
• 32761 = 181², centered hexagonal number
• 32767 = 2¹⁵ − 1, largest positive value for a signed (two's complement) 16-bit integer on a computer.
• 32768 = 2¹⁵ = 8⁵, maximum absolute value of a negative value for a signed (two's complement) 16-bit integer on a computer.
• 32800 = pentagonal pyramidal number^[3]
• 32993 = Leyland number^[9]

33000 to 33999

• 33333 = repdigit
• 33461 = Pell number,^[10] Markov number^[11]
• 33511 = square pyramidal number
• 33781 = octahedral number^[4]

34000 to 34999

• 34560 = 5 superfactorial^[12]
• 34790 = number of non-isomorphic set-systems of weight 13.
• 34841 = start of a prime quadruplet^[6]
• 34969 = favorite number of the Muppet character Count von Count^[13]

35000 to 35999

• 35720 = square pyramidal number
• 35840 = number of ounces in a long ton (2,240 pounds)
• 35890 = tribonacci number^[14]
• 35899 = alternating factorial^[15]
• 35937 = 33³, chiliagonal number^[16]
• 35964 = digit-reassembly number

36000 to 36999

• 36100 = sum of the cubes of the first 19 positive integers
• 36463 – number of parallelogram polyominoes with 14 cells^[17]
• 36594 = octahedral number^[4]

37000 to 37999

• 37378 = semi-meandric number^[18]
• 37634 = third term of the Lucas–Lehmer sequence
• 37666 = Markov number^[11]
• 37926 = pentagonal pyramidal number^[3]

38000 to 38999

• 38024 = square pyramidal number
• 38209 = n such that n | (3ⁿ + 5)^[19]
• 38416 = 14⁴
• 38807 = number of non-equivalent ways of expressing 10,000,000 as the sum of two prime numbers^[20]
• 38962 = Kaprekar number^[21]

39000 to 39999

• 39304 = 34³
• 39559 = octahedral number^[4]
• 39648 = tetranacci number^[22]

Primes

There are 958 prime numbers between 30000 and 40000.