20231311021 has 4 divisors (see below), whose sum is σ = 20231856700. Its totient is φ = 20230765344.

The previous prime is 20231310973. The next prime is 20231311073. The reversal of 20231311021 is 12011313202.

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 11279502025 + 8951808996 = 106205^2 + 94614^2 .

It is a cyclic number.

It is not a de Polignac number, because 20231311021 - 2¹¹ = 20231308973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20231310986 and 20231311004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20231311081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212826 + ... + 292843.

It is an arithmetic number, because the mean of its divisors is an integer number (5057964175).

Almost surely, 2^20231311021 is an apocalyptic number.

It is an amenable number.

20231311021 is a deficient number, since it is larger than the sum of its proper divisors (545679).

20231311021 is an equidigital number, since it uses as much as digits as its factorization.

20231311021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545678.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 20231311021 its reverse (12011313202), we get a palindrome (32242624223).

The spelling of 20231311021 in words is "twenty billion, two hundred thirty-one million, three hundred eleven thousand, twenty-one".