670

670 = 2 × 5 × 67, sphenic number, octahedral number,nontotient 671 = 11 × 61. This number is the magic constant of n×n normal magic square and n-queens problem for n = 11. 672 = 25 × 3 × 7, harmonic divisor number, Zuckerman number, admirable number, largely composite number.