2121330321221 has 4 divisors (see below), whose sum is σ = 2121570055500. Its totient is φ = 2121090586944.

The previous prime is 2121330321211. The next prime is 2121330321239. The reversal of 2121330321221 is 1221230331212.

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 147344661025 + 1973985660196 = 383855^2 + 1404986^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121330321221 - 2²⁶ = 2121263212357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121330321211) 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, 119853866 + ... + 119871563.

It is an arithmetic number, because the mean of its divisors is an integer number (530392513875).

Almost surely, 2^{2121330321221} is an apocalyptic number.

It is an amenable number.

2121330321221 is a deficient number, since it is larger than the sum of its proper divisors (239734279).

2121330321221 is an equidigital number, since it uses as much as digits as its factorization.

2121330321221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239734278.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 2121330321221 its reverse (1221230331212), we get a palindrome (3342560652433).

Subtracting from 2121330321221 its reverse (1221230331212), we obtain a palindrome (900099990009).

The spelling of 2121330321221 in words is "two trillion, one hundred twenty-one billion, three hundred thirty million, three hundred twenty-one thousand, two hundred twenty-one".