213021251221 has 4 divisors (see below), whose sum is σ = 213031101772. Its totient is φ = 213011400672.

The previous prime is 213021251207. The next prime is 213021251237. The reversal of 213021251221 is 122152120312.

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 179470002321 + 33551248900 = 423639^2 + 183170^2 .

It is a cyclic number.

It is not a de Polignac number, because 213021251221 - 2²⁹ = 212484380309 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213021251192 and 213021251201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213021251621) 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, 4892766 + ... + 4936111.

It is an arithmetic number, because the mean of its divisors is an integer number (53257775443).

Almost surely, 2^213021251221 is an apocalyptic number.

It is an amenable number.

213021251221 is a deficient number, since it is larger than the sum of its proper divisors (9850551).

213021251221 is an equidigital number, since it uses as much as digits as its factorization.

213021251221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9850550.

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 213021251221 its reverse (122152120312), we get a palindrome (335173371533).

The spelling of 213021251221 in words is "two hundred thirteen billion, twenty-one million, two hundred fifty-one thousand, two hundred twenty-one".