Jabarkan 640-an dari 600 (nombor) dalam bahasa melayu

640 = 27 × 5, nombor Harshad

641 nombor perdana, Sophie Germain prime, factor of 4294967297 (the smallest nonprime Fermat number), Chen prime, Eisenstein prime with no imaginary part, Proth prime

642 = 2 × 3 × 107, nombor sphenik

643 nombor perdana, largest prime factor of 123456

644 = 22 × 7 × 23, tak totient, nombor Harshad. Common umask.

645 = 3 × 5 × 43, nombor sphenik, Smith number, nombor Harshad

646 = 2 × 17 × 19, nombor sphenik, also ISO 646 is the ISO's standard for international 7-bit variants of ASCII

647 nombor perdana, sum of five consecutive primes (113 + 127 + 131 + 137 + 139), Chen prime, Eisenstein prime with no imaginary part

648 = 23 × 34, nombor Harshad

649 = 11 × 59