575

575 = 5 x 5 x 23.

575 is a palindrome that is 1 less than a square (576 = 24²).

575 is 353 in base 13 (A029968).

575 is a centered octahedral number (A001845).

575 is the number of quadrilaterals that can be formed with perimeter 53 (in other words, partitions of 53 into four parts such that the sum of any three is more than the fourth) (A062890).

Source: What's Special About This Number?