existance of odd digital number
Source: Tuymaada 2016. Juniors/P6
July 22, 2016
number theory
Problem Statement
Is there a positive integer such that all its decimal digits are odd,
the numbers of digits 1, 3, 5, 7, 9 in its decimal representation are equal,
and it is divisible by each 20-digit number obtained from it by deleting
digits? (Neither deleted nor remaining digits must be consecutive.)