12121320221 has 4 divisors (see below), whose sum is σ = 12139331772. Its totient is φ = 12103308672.

The previous prime is 12121320193. The next prime is 12121320223. The reversal of 12121320221 is 12202312121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7244392996 + 4876927225 = 85114^2 + 69835^2 .

It is a cyclic number.

It is not a de Polignac number, because 12121320221 - 2³⁰ = 11047578397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12121320221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12121320223) 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 3 ways as a sum of consecutive naturals, for example, 9004766 + ... + 9006111.

It is an arithmetic number, because the mean of its divisors is an integer number (3034832943).

Almost surely, 2^12121320221 is an apocalyptic number.

It is an amenable number.

12121320221 is a deficient number, since it is larger than the sum of its proper divisors (18011551).

12121320221 is an equidigital number, since it uses as much as digits as its factorization.

12121320221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18011550.

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

Adding to 12121320221 its reverse (12202312121), we get a palindrome (24323632342).

The spelling of 12121320221 in words is "twelve billion, one hundred twenty-one million, three hundred twenty thousand, two hundred twenty-one".