12121 is nontrivially palindromic in base 10.
12121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
12121 is an undulating number in base 10.
12121 is a lucky number.
It is a plaindrome in base 14.
It is a congruent number.
212121 is an apocalyptic number.
It is an amenable number.
12121 is a wasteful number, since it uses less digits than its factorization.
12121 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 71.
The square root of 12121 is about 110.0954131651. The cubic root of 12121 is about 22.9709778872.
The spelling of 12121 in words is "twelve thousand, one hundred twenty-one", and thus it is an iban number.