Definition
Palindromic number
A palindromic number has written digits that appear in the same order forwards and backwards.
What it means
Start at the two ends and move inward. The outside digits must match, then the next pair, and so on. A one-digit number also reads the same in both directions.
Remember it
Fold the digit row at the middle: matching positions should meet.
Example
63,236 has the digit sequence 6–3–2–3–6. Reading from either end gives the same sequence, so it is palindromic.
Watch for
Use the numeral as it is normally written; do not add leading zeros. Therefore 10 is not palindromic just because 010 would read the same both ways.
Common mix-up
A palindrome word and a palindromic number share the same-both-ways pattern, but this term is specifically about digits.
Exact meaning
A palindromic number is a number whose numeral has the same sequence of digits when read from left to right or from right to left.