20121231213 has 12 divisors (see below), whose sum is σ = 29074949280. Its totient is φ = 13409100936.

The previous prime is 20121231149. The next prime is 20121231223. The reversal of 20121231213 is 31213212102.

20121231213 is a `hidden beast` number, since 201 + 21 + 231 + 213 = 666.

It is not a de Polignac number, because 20121231213 - 2⁶ = 20121231149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121231223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 395803 + ... + 443736.

It is an arithmetic number, because the mean of its divisors is an integer number (2422912440).

Almost surely, 2^20121231213 is an apocalyptic number.

It is an amenable number.

20121231213 is a deficient number, since it is larger than the sum of its proper divisors (8953718067).

20121231213 is a wasteful number, since it uses less digits than its factorization.

20121231213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 842208 (or 842205 counting only the distinct ones).

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

Adding to 20121231213 its reverse (31213212102), we get a palindrome (51334443315).

The spelling of 20121231213 in words is "twenty billion, one hundred twenty-one million, two hundred thirty-one thousand, two hundred thirteen".