213222221 has 4 divisors (see below), whose sum is σ = 217758912. Its totient is φ = 208685532.

The previous prime is 213222197. The next prime is 213222223. The reversal of 213222221 is 122222312.

213222221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213222221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 213222221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213222223) 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, 2268275 + ... + 2268368.

It is an arithmetic number, because the mean of its divisors is an integer number (54439728).

Almost surely, 2^213222221 is an apocalyptic number.

It is an amenable number.

213222221 is a deficient number, since it is larger than the sum of its proper divisors (4536691).

213222221 is an equidigital number, since it uses as much as digits as its factorization.

213222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4536690.

The product of its digits is 192, while the sum is 17.

The square root of 213222221 is about 14602.1307006889. The cubic root of 213222221 is about 597.4168774968.

Adding to 213222221 its reverse (122222312), we get a palindrome (335444533).

Subtracting from 213222221 its reverse (122222312), we obtain a palindrome (90999909).

The spelling of 213222221 in words is "two hundred thirteen million, two hundred twenty-two thousand, two hundred twenty-one".