21311132321 has 4 divisors (see below), whose sum is σ = 21332812992. Its totient is φ = 21289451652.

The previous prime is 21311132263. The next prime is 21311132341. The reversal of 21311132321 is 12323111312.

It is a happy number.

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 21311132321 - 2¹⁴ = 21311115937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21311132293 and 21311132302.

It is not an unprimeable number, because it can be changed into a prime (21311132341) 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, 10838861 + ... + 10840826.

It is an arithmetic number, because the mean of its divisors is an integer number (5333203248).

Almost surely, 2^21311132321 is an apocalyptic number.

It is an amenable number.

21311132321 is a deficient number, since it is larger than the sum of its proper divisors (21680671).

21311132321 is an equidigital number, since it uses as much as digits as its factorization.

21311132321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21680670.

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

Adding to 21311132321 its reverse (12323111312), we get a palindrome (33634243633).

The spelling of 21311132321 in words is "twenty-one billion, three hundred eleven million, one hundred thirty-two thousand, three hundred twenty-one".