643 (the 117th prime)

 
Next prime647
Previous prime641
Octal(1203)8
Hexadecimal(283)16
Prime gap4
29th Cousin prime (the small number)The big number is 647 .
56th Prime of the Form 3n+1202 + 3 * 92
61st Prime of the Form 4n+3 
38th Left-truncatable prime