21213231321211 has 4 divisors (see below), whose sum is σ = 21250512923400. Its totient is φ = 21175949719024.

The previous prime is 21213231321199. The next prime is 21213231321229. The reversal of 21213231321211 is 11212313231212.

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

It is a cyclic number.

It is not a de Polignac number, because 21213231321211 - 2²⁷ = 21213097103483 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213231391211) 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, 18640800241 + ... + 18640801378.

It is an arithmetic number, because the mean of its divisors is an integer number (5312628230850).

Almost surely, 2^{21213231321211} is an apocalyptic number.

21213231321211 is a deficient number, since it is larger than the sum of its proper divisors (37281602189).

21213231321211 is an equidigital number, since it uses as much as digits as its factorization.

21213231321211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37281602188.

The product of its digits is 864, while the sum is 25.

Adding to 21213231321211 its reverse (11212313231212), we get a palindrome (32425544552423).

The spelling of 21213231321211 in words is "twenty-one trillion, two hundred thirteen billion, two hundred thirty-one million, three hundred twenty-one thousand, two hundred eleven".