213220321 has 2 divisors, whose sum is σ = 213220322. Its totient is φ = 213220320.

The previous prime is 213220253. The next prime is 213220339. The reversal of 213220321 is 123022312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 159769600 + 53450721 = 12640^2 + 7311^2 .

It is a cyclic number.

It is not a de Polignac number, because 213220321 - 2¹⁵ = 213187553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213220295 and 213220304.

It is not a weakly prime, because it can be changed into another prime (213220351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106610160 + 106610161.

It is an arithmetic number, because the mean of its divisors is an integer number (106610161).

Almost surely, 2^213220321 is an apocalyptic number.

It is an amenable number.

213220321 is a deficient number, since it is larger than the sum of its proper divisors (1).

213220321 is an equidigital number, since it uses as much as digits as its factorization.

213220321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 213220321 is about 14602.0656415454. The cubic root of 213220321 is about 597.4151029860.

Adding to 213220321 its reverse (123022312), we get a palindrome (336242633).

The spelling of 213220321 in words is "two hundred thirteen million, two hundred twenty thousand, three hundred twenty-one".