30.2. Find the largest natural number that is divisible by 37 and in which each subsequent digit is less than the previous one.

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30.2. The largest natural number with decreasing digits is the ten-digit number 9876543210. We will divide it by 37. During the division, we notice that it is not divisible by 37, whereas the eight-digit number 98765432 is divisible by 37. Therefore, the nine-digit number 987654320 is also divisible by 37. It is evident that it will be the largest among the nine-digit numbers where each subsequent digit is less than the previous one, i.e., it will be the answer to the problem.