The
unitary divisors of an
integer n are those pairs of integers
a and
b satisfying
ab = n and
(a,b) = 1.
*
For example, the unitary divisors of 99 are 1, 9, 11 and 99 (but not 3 or 33).
*Here (a,b) denotes, as usual, the greatest common divisor of a and b; thus, the condition (a,b) = 1 means that a and b have no factors in common which are greater than 1.