21310312321 has 4 divisors (see below), whose sum is σ = 21628376752. Its totient is φ = 20992247892.

The previous prime is 21310312313. The next prime is 21310312343. The reversal of 21310312321 is 12321301312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21310312321 - 2³ = 21310312313 is a prime.

It is a super-2 number, since 2×21310312321² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21310319321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159032115 + ... + 159032248.

It is an arithmetic number, because the mean of its divisors is an integer number (5407094188).

Almost surely, 2^21310312321 is an apocalyptic number.

It is an amenable number.

21310312321 is a deficient number, since it is larger than the sum of its proper divisors (318064431).

21310312321 is an equidigital number, since it uses as much as digits as its factorization.

21310312321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318064430.

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

Adding to 21310312321 its reverse (12321301312), we get a palindrome (33631613633).

The spelling of 21310312321 in words is "twenty-one billion, three hundred ten million, three hundred twelve thousand, three hundred twenty-one".