20123031221 has 4 divisors (see below), whose sum is σ = 20141376012. Its totient is φ = 20104686432.

The previous prime is 20123031217. The next prime is 20123031259. The reversal of 20123031221 is 12213032102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10847222500 + 9275808721 = 104150^2 + 96311^2 .

It is a cyclic number.

It is not a de Polignac number, because 20123031221 - 2² = 20123031217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20123031221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123034221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9170750 + ... + 9172943.

It is an arithmetic number, because the mean of its divisors is an integer number (5035344003).

Almost surely, 2^20123031221 is an apocalyptic number.

It is an amenable number.

20123031221 is a deficient number, since it is larger than the sum of its proper divisors (18344791).

20123031221 is a wasteful number, since it uses less digits than its factorization.

20123031221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18344790.

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

Adding to 20123031221 its reverse (12213032102), we get a palindrome (32336063323).

The spelling of 20123031221 in words is "twenty billion, one hundred twenty-three million, thirty-one thousand, two hundred twenty-one".