20130231221 has 4 divisors (see below), whose sum is σ = 20130530700. Its totient is φ = 20129931744.

The previous prime is 20130231217. The next prime is 20130231223. The reversal of 20130231221 is 12213203102.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12213203102 = 2 ⋅6106601551.

It can be written as a sum of positive squares in 2 ways, for example, as 5894400625 + 14235830596 = 76775^2 + 119314^2 .

It is a cyclic number.

It is not a de Polignac number, because 20130231221 - 2² = 20130231217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20130231221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20130231223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3065 + ... + 200673.

It is an arithmetic number, because the mean of its divisors is an integer number (5032632675).

Almost surely, 2^20130231221 is an apocalyptic number.

It is an amenable number.

20130231221 is a deficient number, since it is larger than the sum of its proper divisors (299479).

20130231221 is a wasteful number, since it uses less digits than its factorization.

20130231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299478.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 20130231221 its reverse (12213203102), we get a palindrome (32343434323).

The spelling of 20130231221 in words is "twenty billion, one hundred thirty million, two hundred thirty-one thousand, two hundred twenty-one".