605 has a sum of digits equal to its largest prime factor (11).
605 has a representation as a sum of two squares: 605 = 112 + 222.
605 is a member of the sequence obtained by starting with 1, then repeatedly reversing the digits and adding 2: 1, 3, 5, 7, 9, 11, 13, 33, 35, . . . , 306, 605, 508, . . .
605 is the telephone area code for the state of South Dakota.
Source: What’s Special About This Number?
605 is the telephone area code for the state of South Dakota.
Source: What’s Special About This Number?
