21031121323 has 4 divisors (see below), whose sum is σ = 21034192608. Its totient is φ = 21028050040.

The previous prime is 21031121273. The next prime is 21031121347. The reversal of 21031121323 is 32312113012.

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 21031121323 - 2²⁹ = 20494250411 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 21031121323.

It is not an unprimeable number, because it can be changed into a prime (21331121323) 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, 1525348 + ... + 1539073.

It is an arithmetic number, because the mean of its divisors is an integer number (5258548152).

Almost surely, 2^21031121323 is an apocalyptic number.

21031121323 is a deficient number, since it is larger than the sum of its proper divisors (3071285).

21031121323 is an equidigital number, since it uses as much as digits as its factorization.

21031121323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3071284.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21031121323 its reverse (32312113012), we get a palindrome (53343234335).

The spelling of 21031121323 in words is "twenty-one billion, thirty-one million, one hundred twenty-one thousand, three hundred twenty-three".