20211231213 has 56 divisors (see below), whose sum is σ = 30817983168. Its totient is φ = 13246431552.

The previous prime is 20211231197. The next prime is 20211231217. The reversal of 20211231213 is 31213211202.

It is not a de Polignac number, because 20211231213 - 2⁴ = 20211231197 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211231217) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 31238056 + ... + 31238702.

It is an arithmetic number, because the mean of its divisors is an integer number (550321128).

Almost surely, 2^20211231213 is an apocalyptic number.

It is an amenable number.

20211231213 is a deficient number, since it is larger than the sum of its proper divisors (10606751955).

20211231213 is an frugal number, since it uses more digits than its factorization.

20211231213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1325 (or 1310 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 20211231213 its reverse (31213211202), we get a palindrome (51424442415).

The spelling of 20211231213 in words is "twenty billion, two hundred eleven million, two hundred thirty-one thousand, two hundred thirteen".