9,709

[Math.]  97093 = 915,215,787,829 has each of its digits occurring twice. (References [17])

 

9,720

[Math.]  Sum (in degrees) of all internal angles of a 56-side polygon.

 

9,723

[Math.]  Each ratio 48615/9723 = 5, using each of 9 digits 1-9 once, shows how to arrange a 9-book set on 2 shelves to mark the book #5.

 

9,730

[Math.]  A triangular number (sum of all integers from 1 to 139): 9730 = 1+2+…+138+139.

 

9,742

[Math.]  The largest number that the differences between any of its two digits is always prime.

 

9,753

[Math.]  Two multiples of number 9753, 9753×4 = 39,012 and 9753×5 = 48,765, use each of 10 digits 0-9 once.

 

9,786

[Math.]  Two multiples of number 4893, 4893×2 = 9,786 and 4893×7 = 34,251, use each of 9 digits 1-9 once.