121121212221 has 8 divisors (see below), whose sum is σ = 179438832960. Its totient is φ = 80747474796.

The previous prime is 121121212207. The next prime is 121121212271. The reversal of 121121212221 is 122212121121.

121121212221 is a `hidden beast` number, since 1 + 211 + 21 + 212 + 221 = 666.

It is not a de Polignac number, because 121121212221 - 2¹⁴ = 121121195837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121121212194 and 121121212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121121212271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2242985385 + ... + 2242985438.

It is an arithmetic number, because the mean of its divisors is an integer number (22429854120).

Almost surely, 2^121121212221 is an apocalyptic number.

It is an amenable number.

121121212221 is a deficient number, since it is larger than the sum of its proper divisors (58317620739).

121121212221 is an equidigital number, since it uses as much as digits as its factorization.

121121212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4485970832 (or 4485970826 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 121121212221 its reverse (122212121121), we get a palindrome (243333333342).

The spelling of 121121212221 in words is "one hundred twenty-one billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".