Well, 1 is equal to 1. 9 is equal to 9. So any number from 0 to 9. I do not think this is what is meant by the question. If you mean any number with more than one digit. There is no such number. Because 11 sums to 2. 19 sums to 10. 21 sums to 3. 29 sums to 11. 111 sums 3. 119 sums to 11. The sums do not grow as fast the increase of digits.
56
21
18 is the only number that matches these criteria.
A dozen is equal to 12. The sum of the digits of 12 are 1 + 2 = 3.
The number is 45. The sum of its digits i.e. 4+5=9 Five times the sum of its digits i.e. 5 times 9 which is 45
8 is the same as the sum of the digits of its cube, 512.
1
81
Any number whose sum of its digits are equal to a multiple of 3, is divisible by 3. In this instance, the sum of the digits of the number 34215 is equal to 15, which is divisible by 3, and therefore the number is divisible by 3.
26
36
412
The number is 36.
53
56
a neon number is that where sum of cube of digits of a number is equal to the cube of number itself.
153....