213311221 has 2 divisors, whose sum is σ = 213311222. Its totient is φ = 213311220.

The previous prime is 213311213. The next prime is 213311311. The reversal of 213311221 is 122113312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203632900 + 9678321 = 14270^2 + 3111^2 .

It is a cyclic number.

It is not a de Polignac number, because 213311221 - 2³ = 213311213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213311195 and 213311204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213311201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106655610 + 106655611.

It is an arithmetic number, because the mean of its divisors is an integer number (106655611).

Almost surely, 2^213311221 is an apocalyptic number.

It is an amenable number.

213311221 is a deficient number, since it is larger than the sum of its proper divisors (1).

213311221 is an equidigital number, since it uses as much as digits as its factorization.

213311221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 16.

The square root of 213311221 is about 14605.1778832029. The cubic root of 213311221 is about 597.4999875119.

Adding to 213311221 its reverse (122113312), we get a palindrome (335424533).

The spelling of 213311221 in words is "two hundred thirteen million, three hundred eleven thousand, two hundred twenty-one".