21210131321023 has 4 divisors (see below), whose sum is σ = 21661410710880. Its totient is φ = 20758851931168.

The previous prime is 21210131321021. The next prime is 21210131321107. The reversal of 21210131321023 is 32012313101212.

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

It is a cyclic number.

It is not a de Polignac number, because 21210131321023 - 2¹ = 21210131321021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210131320985 and 21210131321003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210131321021) 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, 225639694858 + ... + 225639694951.

It is an arithmetic number, because the mean of its divisors is an integer number (5415352677720).

Almost surely, 2^{21210131321023} is an apocalyptic number.

21210131321023 is a deficient number, since it is larger than the sum of its proper divisors (451279389857).

21210131321023 is an equidigital number, since it uses as much as digits as its factorization.

21210131321023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451279389856.

The product of its (nonzero) digits is 432, while the sum is 22.

Adding to 21210131321023 its reverse (32012313101212), we get a palindrome (53222444422235).

The spelling of 21210131321023 in words is "twenty-one trillion, two hundred ten billion, one hundred thirty-one million, three hundred twenty-one thousand, twenty-three".