21312321311 has 16 divisors (see below), whose sum is σ = 21861348768. Its totient is φ = 20771251200.

The previous prime is 21312321307. The next prime is 21312321319. The reversal of 21312321311 is 11312321312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21312321311 - 2² = 21312321307 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312321319) 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 15 ways as a sum of consecutive naturals, for example, 3285191 + ... + 3291671.

It is an arithmetic number, because the mean of its divisors is an integer number (1366334298).

Almost surely, 2^21312321311 is an apocalyptic number.

21312321311 is a deficient number, since it is larger than the sum of its proper divisors (549027457).

21312321311 is a wasteful number, since it uses less digits than its factorization.

21312321311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7082.

The product of its digits is 216, while the sum is 20.

Adding to 21312321311 its reverse (11312321312), we get a palindrome (32624642623).

Subtracting from 21312321311 its reverse (11312321312), we obtain a palindrome (9999999999).

The spelling of 21312321311 in words is "twenty-one billion, three hundred twelve million, three hundred twenty-one thousand, three hundred eleven".