For a positive integer n denote by P0(n) the product of all non-zero digits of n. Let N0 be the set of all positive integers n such that P0(n)∣n. Find the largest possible value of ℓ such that N0 contains infinitely many strings of ℓ consecutive integers.Proposed by Navid Safaei, Iran number theory unsolvednumber theorynumber theory proposedDivisibility