MathDB
TOT 108 1986 Spring J2 each digit of decimal repr. of N divides N

Source:

August 29, 2019
number theorymaximumDigitsDivide

Problem Statement

A natural number NN is written in its decimal representation . It is known that for each digit in this representation , this digit divides exactly into the number NN (the digit 00 is not encountered). What is the maximum number of different digits which there can be in such a representation of NN?
(S . Fomin, Leningrad)