221331213 has 12 divisors (see below), whose sum is σ = 320030620. Its totient is φ = 147401856.

The previous prime is 221331199. The next prime is 221331251. The reversal of 221331213 is 312133122.

It can be written as a sum of positive squares in 2 ways, for example, as 69006249 + 152324964 = 8307^2 + 12342^2 .

It is not a de Polignac number, because 221331213 - 2⁴ = 221331197 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 (221331283) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3106 + ... + 21267.

Almost surely, 2^221331213 is an apocalyptic number.

It is an amenable number.

221331213 is a deficient number, since it is larger than the sum of its proper divisors (98699407).

221331213 is a wasteful number, since it uses less digits than its factorization.

221331213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25388 (or 25385 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 221331213 is about 14877.2044753038. The cubic root of 221331213 is about 604.8962443023.

Adding to 221331213 its reverse (312133122), we get a palindrome (533464335).

The spelling of 221331213 in words is "two hundred twenty-one million, three hundred thirty-one thousand, two hundred thirteen".