20211231123 has 24 divisors (see below), whose sum is σ = 29356629120. Its totient is φ = 13399296000.

The previous prime is 20211231109. The next prime is 20211231143. The reversal of 20211231123 is 32113211202.

It is not a de Polignac number, because 20211231123 - 2¹⁶ = 20211165587 is a prime.

It is a super-2 number, since 2×20211231123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20211231096 and 20211231105.

It is not an unprimeable number, because it can be changed into a prime (20211231143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1255123 + ... + 1271123.

It is an arithmetic number, because the mean of its divisors is an integer number (1223192880).

Almost surely, 2^20211231123 is an apocalyptic number.

20211231123 is a deficient number, since it is larger than the sum of its proper divisors (9145397997).

20211231123 is a wasteful number, since it uses less digits than its factorization.

20211231123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16779 (or 16776 counting only the distinct ones).

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

Adding to 20211231123 its reverse (32113211202), we get a palindrome (52324442325).

The spelling of 20211231123 in words is "twenty billion, two hundred eleven million, two hundred thirty-one thousand, one hundred twenty-three".