20323031021 has 4 divisors (see below), whose sum is σ = 21518503452. Its totient is φ = 19127558592.

The previous prime is 20323030999. The next prime is 20323031039. The reversal of 20323031021 is 12013032302.

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 8385064900 + 11937966121 = 91570^2 + 109261^2 .

It is a cyclic number.

It is not a de Polignac number, because 20323031021 - 2²⁶ = 20255922157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1195472413 = 20323031021 / (2 + 0 + 3 + 2 + 3 + 0 + 3 + 1 + 0 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20323031621) 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, 597736190 + ... + 597736223.

It is an arithmetic number, because the mean of its divisors is an integer number (5379625863).

Almost surely, 2^20323031021 is an apocalyptic number.

It is an amenable number.

20323031021 is a deficient number, since it is larger than the sum of its proper divisors (1195472431).

20323031021 is a wasteful number, since it uses less digits than its factorization.

20323031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1195472430.

The product of its (nonzero) digits is 216, while the sum is 17.

Adding to 20323031021 its reverse (12013032302), we get a palindrome (32336063323).

The spelling of 20323031021 in words is "twenty billion, three hundred twenty-three million, thirty-one thousand, twenty-one".