20221231 has 2 divisors, whose sum is σ = 20221232. Its totient is φ = 20221230.

The previous prime is 20221213. The next prime is 20221259. The reversal of 20221231 is 13212202.

Together with previous prime (20221213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20221231 - 2¹¹ = 20219183 is a prime.

It is a super-2 number, since 2×20221231² = 817796366310722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20221261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10110615 + 10110616.

It is an arithmetic number, because the mean of its divisors is an integer number (10110616).

Almost surely, 2^20221231 is an apocalyptic number.

20221231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20221231 is an equidigital number, since it uses as much as digits as its factorization.

20221231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 20221231 is about 4496.8023083075. The cubic root of 20221231 is about 272.4389493735.

Adding to 20221231 its reverse (13212202), we get a palindrome (33433433).

The spelling of 20221231 in words is "twenty million, two hundred twenty-one thousand, two hundred thirty-one".