2121212321 has 2 divisors, whose sum is σ = 2121212322. Its totient is φ = 2121212320.

The previous prime is 2121212311. The next prime is 2121212323. The reversal of 2121212321 is 1232121212.

2121212321 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2091781696 + 29430625 = 45736^2 + 5425^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121212321 - 2²² = 2117018017 is a prime.

Together with 2121212323, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 2121212321.

It is not a weakly prime, because it can be changed into another prime (2121212323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060606160 + 1060606161.

It is an arithmetic number, because the mean of its divisors is an integer number (1060606161).

Almost surely, 2^2121212321 is an apocalyptic number.

It is an amenable number.

2121212321 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121212321 is an equidigital number, since it uses as much as digits as its factorization.

2121212321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 17.

The square root of 2121212321 is about 46056.6208161215. The cubic root of 2121212321 is about 1284.8764830532.

Adding to 2121212321 its reverse (1232121212), we get a palindrome (3353333533).

It can be divided in two parts, 21212 and 12321, that added together give a palindrome (33533).

The spelling of 2121212321 in words is "two billion, one hundred twenty-one million, two hundred twelve thousand, three hundred twenty-one".