In this article we show that if V is the variety of polynilpotent
groups of class row (c1,c2,...,cs),Nc1,c2,...,cs, and
G≅Zpα1∗nZpα2∗n...∗nZpαt
is the nth nilpotent product of some cyclic p-groups, where c1≥n,
α1≥α2≥...≥αt and (q,p)=1 for all primes
q less than or equal to n, then ∣Nc1,c2,...,csM(G)∣=pdm if and only if G≅Zp∗nZp∗n...∗nZp (m-copies), where
m=∑i=1tαi and dm=χcs+1(...(χc2+1(∑j=1nχc1+j(m)))...). Also, we extend the result to the multiple nilpotent
product G≅Zpα1∗n1Zpα2∗n2...∗nt−1Zpαt, where c1≥n1≥...≥nt−1. Finally a similar result is given
for the c-nilpotent multiplier of G≅Zpα1∗nZpα2∗n...∗nZpαt
with the different conditions n≥c and (q,p)=1 for all primes q less
than or equal to n+c.Comment: 10 page