Answer
37837800 ways
Work Step by Step
We have, number of objects (n) = 15
Number of distinguishable boxes (k) = 5
$N_{i}$ = Number of objects in ith box
$N_{1}$ = 1
$N_{2}$ = 2
$N_{3}$ = 3
$N_{4}$ = 4
$N_{5}$ = 5
Distributing n distinguishable objects into k distinguishable boxes such that $N_{i}$ objects are in the box can be done in $\frac{n!}{N1!N2!..Nk!}$ ways
So $\frac{15!}{1!2!3!4!5!}$=37837800 ways