2121123321221 has 4 divisors (see below), whose sum is σ = 2121766284000. Its totient is φ = 2120480358444.

The previous prime is 2121123321157. The next prime is 2121123321227. The reversal of 2121123321221 is 1221233211212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2121123321221 - 2⁶ = 2121123321157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121123321227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321476441 + ... + 321483038.

It is an arithmetic number, because the mean of its divisors is an integer number (530441571000).

Almost surely, 2^{2121123321221} is an apocalyptic number.

It is an amenable number.

2121123321221 is a deficient number, since it is larger than the sum of its proper divisors (642962779).

2121123321221 is an equidigital number, since it uses as much as digits as its factorization.

2121123321221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642962778.

The product of its digits is 576, while the sum is 23.

Adding to 2121123321221 its reverse (1221233211212), we get a palindrome (3342356532433).

The spelling of 2121123321221 in words is "two trillion, one hundred twenty-one billion, one hundred twenty-three million, three hundred twenty-one thousand, two hundred twenty-one".