21321322313 has 4 divisors (see below), whose sum is σ = 21321800580. Its totient is φ = 21320844048.

The previous prime is 21321322289. The next prime is 21321322349. The reversal of 21321322313 is 31322312312.

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 772673209 + 20548649104 = 27797^2 + 143348^2 .

It is a cyclic number.

It is not a de Polignac number, because 21321322313 - 2¹⁰ = 21321321289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21321322513) 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, 164498 + ... + 264011.

It is an arithmetic number, because the mean of its divisors is an integer number (5330450145).

Almost surely, 2^21321322313 is an apocalyptic number.

It is an amenable number.

21321322313 is a deficient number, since it is larger than the sum of its proper divisors (478267).

21321322313 is an equidigital number, since it uses as much as digits as its factorization.

21321322313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478266.

The product of its digits is 1296, while the sum is 23.

Adding to 21321322313 its reverse (31322312312), we get a palindrome (52643634625).

The spelling of 21321322313 in words is "twenty-one billion, three hundred twenty-one million, three hundred twenty-two thousand, three hundred thirteen".