213220121221 has 2 divisors, whose sum is σ = 213220121222. Its totient is φ = 213220121220.

The previous prime is 213220121171. The next prime is 213220121239. The reversal of 213220121221 is 122121022312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151601988321 + 61618132900 = 389361^2 + 248230^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213220121221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213220121281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106610060610 + 106610060611.

It is an arithmetic number, because the mean of its divisors is an integer number (106610060611).

Almost surely, 2^213220121221 is an apocalyptic number.

It is an amenable number.

213220121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

213220121221 is an equidigital number, since it uses as much as digits as its factorization.

213220121221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 213220121221 its reverse (122121022312), we get a palindrome (335341143533).

The spelling of 213220121221 in words is "two hundred thirteen billion, two hundred twenty million, one hundred twenty-one thousand, two hundred twenty-one".