type Reverse<S extends string> =
  S extends `${infer S1}${infer S2}` ? `${Reverse<S2>}${S1}` : ""
type IsPalindromeImpl<S extends string, T extends string=Reverse<S>> =
  S extends `${infer S1}${infer S2}`
  ? T extends `${infer T1}${infer T2}`
    ? S1 extends T1
      ? IsPalindromeImpl<S2,T2>
      : false
    : never
  : true
type IsPalindrome<T extends string | number> = IsPalindromeImpl<`${T}`>

import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<IsPalindrome<'abc'>, false>>,
  Expect<Equal<IsPalindrome<'b'>, true>>,
  Expect<Equal<IsPalindrome<'abca'>, false>>,
  Expect<Equal<IsPalindrome<121>, true>>,
  Expect<Equal<IsPalindrome<19260817>, false>>,
]