20121231221 has 8 divisors (see below), whose sum is σ = 24764592384. Its totient is φ = 15920094960.

The previous prime is 20121231149. The next prime is 20121231223. The reversal of 20121231221 is 12213212102.

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

It is not a de Polignac number, because 20121231221 - 2³⁰ = 19047489397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121231221.

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 7 ways as a sum of consecutive naturals, for example, 110556125 + ... + 110556306.

It is an arithmetic number, because the mean of its divisors is an integer number (3095574048).

Almost surely, 2^20121231221 is an apocalyptic number.

It is an amenable number.

20121231221 is a deficient number, since it is larger than the sum of its proper divisors (4643361163).

20121231221 is a wasteful number, since it uses less digits than its factorization.

20121231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221112451.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20121231221 its reverse (12213212102), we get a palindrome (32334443323).

The spelling of 20121231221 in words is "twenty billion, one hundred twenty-one million, two hundred thirty-one thousand, two hundred twenty-one".