20211231211 has 4 divisors (see below), whose sum is σ = 20289874392. Its totient is φ = 20132588032.

The previous prime is 20211231197. The next prime is 20211231217. The reversal of 20211231211 is 11213211202.

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 20211231211 - 2⁵ = 20211231179 is a prime.

It is a Duffinian 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 3 ways as a sum of consecutive naturals, for example, 39321205 + ... + 39321718.

It is an arithmetic number, because the mean of its divisors is an integer number (5072468598).

Almost surely, 2^20211231211 is an apocalyptic number.

20211231211 is a deficient number, since it is larger than the sum of its proper divisors (78643181).

20211231211 is an equidigital number, since it uses as much as digits as its factorization.

20211231211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78643180.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 20211231211 its reverse (11213211202), we get a palindrome (31424442413).

The spelling of 20211231211 in words is "twenty billion, two hundred eleven million, two hundred thirty-one thousand, two hundred eleven".