213331331221 has 4 divisors (see below), whose sum is σ = 217356450732. Its totient is φ = 209306211712.

The previous prime is 213331331201. The next prime is 213331331237. The reversal of 213331331221 is 122133133312.

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 161262480625 + 52068850596 = 401575^2 + 228186^2 .

It is a cyclic number.

It is not a de Polignac number, because 213331331221 - 2⁵ = 213331331189 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 (213331331201) 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, 2012559676 + ... + 2012559781.

It is an arithmetic number, because the mean of its divisors is an integer number (54339112683).

Almost surely, 2^213331331221 is an apocalyptic number.

It is an amenable number.

213331331221 is a deficient number, since it is larger than the sum of its proper divisors (4025119511).

213331331221 is an equidigital number, since it uses as much as digits as its factorization.

213331331221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4025119510.

The product of its digits is 1944, while the sum is 25.

Adding to 213331331221 its reverse (122133133312), we get a palindrome (335464464533).

The spelling of 213331331221 in words is "two hundred thirteen billion, three hundred thirty-one million, three hundred thirty-one thousand, two hundred twenty-one".