-6
-1
13 & 14 (169 & 196)
To find how many two-digit numbers have digits whose sum is a perfect square, we first note that the two-digit numbers range from 10 to 99. The possible sums of the digits (tens digit (a) and units digit (b)) can range from 1 (1+0) to 18 (9+9). The perfect squares within this range are 1, 4, 9, and 16. Analyzing each case, we find the valid combinations for each perfect square, leading to a total of 36 two-digit numbers whose digits sum to a perfect square.
Yeah, of course you can: 25, 34, 43, 52, 61, 70
Find a four digit number whose digits will be reversed when multiplied by nine?
Oh, dude, you're asking me to find prime numbers that are also into numerology? That's like asking a pineapple to do algebra. But hey, I'm up for the challenge. The prime numbers whose digits add up to 13 are 499 and 589. Just a couple of cool digits hanging out together, you know?
4 x 578 = 2312 8 x 754 = 6032
Well, 47 49 51 53 are four consecutive odd numbers those total squared has for identical digits. 40000.... The square root of any number that is only four digits long all containing the same digit has a value that is not an integer.
19
47
Write down the numbers from 1000 to 9999.
The numbers are 18 and 20.