213444221 has 4 divisors (see below), whose sum is σ = 213611100. Its totient is φ = 213277344.

The previous prime is 213444193. The next prime is 213444229. The reversal of 213444221 is 122444312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 140683321 + 72760900 = 11861^2 + 8530^2 .

It is a cyclic number.

It is not a de Polignac number, because 213444221 - 2¹⁸ = 213182077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213444229) 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 in 3 ways as a sum of consecutive naturals, for example, 81506 + ... + 84083.

It is an arithmetic number, because the mean of its divisors is an integer number (53402775).

Almost surely, 2^213444221 is an apocalyptic number.

It is an amenable number.

213444221 is a deficient number, since it is larger than the sum of its proper divisors (166879).

213444221 is a wasteful number, since it uses less digits than its factorization.

213444221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166878.

The product of its digits is 1536, while the sum is 23.

The square root of 213444221 is about 14609.7303534323. The cubic root of 213444221 is about 597.6241425495.

Adding to 213444221 its reverse (122444312), we get a palindrome (335888533).

Subtracting from 213444221 its reverse (122444312), we obtain a palindrome (90999909).

The spelling of 213444221 in words is "two hundred thirteen million, four hundred forty-four thousand, two hundred twenty-one".