313 (three hundred [and] thirteen) is the natural number following 312 and preceding 314.
In mathematics
313 is:
- a twin prime with 311
- a centered square number
- a full reptend prime (and the smallest number which is a full reptend prime in base 10 but not in base 2 to 9)
- a Pythagorean prime
- a regular prime
- a palindromic prime in both decimal and binary.
- a truncatable prime
- a weakly prime in base 5
- a happy number
- an Armstrong number - in base 4 ( 3×4<sup>2</sup> + 1×4<sup>1</sup> + 3×4<sup>0</sup> = 3<sup>3</sup> + 1<sup>3</sup> + 3<sup>3</sup> )
- an index of a prime Lucas number.
- a palindromic number in base 2 (100111001)
In religion
- The number of times the word pray appears in the King James Bible.
- The number of soldiers that Muhammad had with him in the first battle fought by the Muslims, the Battle of Badr.