213121302221 has 2 divisors, whose sum is σ = 213121302222. Its totient is φ = 213121302220.

The previous prime is 213121302187. The next prime is 213121302257. The reversal of 213121302221 is 122203121312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203636490121 + 9484812100 = 451261^2 + 97390^2 .

It is a cyclic number.

It is not a de Polignac number, because 213121302221 - 2⁶ = 213121302157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213121302193 and 213121302202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213121302721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106560651110 + 106560651111.

It is an arithmetic number, because the mean of its divisors is an integer number (106560651111).

Almost surely, 2^213121302221 is an apocalyptic number.

It is an amenable number.

213121302221 is a deficient number, since it is larger than the sum of its proper divisors (1).

213121302221 is an equidigital number, since it uses as much as digits as its factorization.

213121302221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 213121302221 its reverse (122203121312), we get a palindrome (335324423533).

The spelling of 213121302221 in words is "two hundred thirteen billion, one hundred twenty-one million, three hundred two thousand, two hundred twenty-one".