Selected numbers

• 90000 – sum of the cubes of the first 24 positive integers
• 90625 – the only five-digit automorphic number
  Automorphic number
  In mathematics an automorphic number is a number whose square "ends" in the same digits as number itself. For example, 52 = 25, 762 = 5776, and 8906252 = 793212890625, so 5, 76 and 890625 are all automorphic numbers.The sequence of automorphic numbers begins 1, 5, 6, 25, 76, 376, 625, 9376, .....
  
  
• 93312 – Leyland number
  Leyland number
  In number theory, a Leyland number is a number of the form xy + yx, where x and y are integers greater than 1. The first few Leyland numbers are...
  
  
• 94932 – Leyland number
• 95121 – Kaprekar number
• 96557 – Markov number
  Markov number
  A Markov number or Markoff number is a positive integer x, y or z that is part of a solution to the Markov Diophantine equationx^2 + y^2 + z^2 = 3xyz,\,studied by .The first few Markov numbers are...
  
  
• 99066 – largest number whose square (algebra) uses all of the decimal
  Decimal
  The decimal numeral system has ten as its base. It is the numerical base most widely used by modern civilizations....
  
   digits
  Numerical digit
  A digit is a symbol used in combinations to represent numbers in positional numeral systems. The name "digit" comes from the fact that the 10 digits of the hands correspond to the 10 symbols of the common base 10 number system, i.e...
  
   once.
• 99999 – Kaprekar number
  Kaprekar number
  In mathematics, a Kaprekar number for a given base is a non-negative integer, the representation of whose square in that base can be split into two parts that add up to the original number again. For instance, 45 is a Kaprekar number, because 45² = 2025 and 20+25 = 45. The Kaprekar numbers are...