20123231021 has 8 divisors (see below), whose sum is σ = 20183331384. Its totient is φ = 20063180800.

The previous prime is 20123231017. The next prime is 20123231069. The reversal of 20123231021 is 12013232102.

It can be written as a sum of positive squares in 4 ways, for example, as 16490155396 + 3633075625 = 128414^2 + 60275^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20123231021 - 2² = 20123231017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123231071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 885821 + ... + 908253.

It is an arithmetic number, because the mean of its divisors is an integer number (2522916423).

Almost surely, 2^20123231021 is an apocalyptic number.

It is an amenable number.

20123231021 is a deficient number, since it is larger than the sum of its proper divisors (60100363).

20123231021 is a wasteful number, since it uses less digits than its factorization.

20123231021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25071.

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

Adding to 20123231021 its reverse (12013232102), we get a palindrome (32136463123).

The spelling of 20123231021 in words is "twenty billion, one hundred twenty-three million, two hundred thirty-one thousand, twenty-one".