20121231 has 8 divisors (see below), whose sum is σ = 28892080. Its totient is φ = 12382272.

The previous prime is 20121193. The next prime is 20121271. The reversal of 20121231 is 13212102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20121231 - 2⁷ = 20121103 is a prime.

It is a super-2 number, since 2×20121231² = 809727873910722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257926 + ... + 258003.

It is an arithmetic number, because the mean of its divisors is an integer number (3611510).

Almost surely, 2^20121231 is an apocalyptic number.

20121231 is a deficient number, since it is larger than the sum of its proper divisors (8770849).

20121231 is a wasteful number, since it uses less digits than its factorization.

20121231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515945.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 20121231 is about 4485.6695152452. The cubic root of 20121231 is about 271.9891098221.

Adding to 20121231 its reverse (13212102), we get a palindrome (33333333).

The spelling of 20121231 in words is "twenty million, one hundred twenty-one thousand, two hundred thirty-one".