21310031321 has 2 divisors, whose sum is σ = 21310031322. Its totient is φ = 21310031320.

The previous prime is 21310031293. The next prime is 21310031333. The reversal of 21310031321 is 12313001312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17705229721 + 3604801600 = 133061^2 + 60040^2 .

It is a cyclic number.

It is not a de Polignac number, because 21310031321 - 2¹⁴ = 21310014937 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21310031321.

It is not a weakly prime, because it can be changed into another prime (21310031621) 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 as a sum of consecutive naturals, namely, 10655015660 + 10655015661.

It is an arithmetic number, because the mean of its divisors is an integer number (10655015661).

Almost surely, 2^21310031321 is an apocalyptic number.

It is an amenable number.

21310031321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310031321 is an equidigital number, since it uses as much as digits as its factorization.

21310031321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21310031321 its reverse (12313001312), we get a palindrome (33623032633).

The spelling of 21310031321 in words is "twenty-one billion, three hundred ten million, thirty-one thousand, three hundred twenty-one".