21311210221 has 8 divisors (see below), whose sum is σ = 24362297024. Its totient is φ = 18261780480.

The previous prime is 21311210209. The next prime is 21311210231. The reversal of 21311210221 is 12201211312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21311210221 - 2⁵ = 21311210189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21311210195 and 21311210204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311210231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 386580 + ... + 438253.

It is an arithmetic number, because the mean of its divisors is an integer number (3045287128).

Almost surely, 2^21311210221 is an apocalyptic number.

It is an amenable number.

21311210221 is a deficient number, since it is larger than the sum of its proper divisors (3051086803).

21311210221 is an equidigital number, since it uses as much as digits as its factorization.

21311210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 828531.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21311210221 its reverse (12201211312), we get a palindrome (33512421533).

The spelling of 21311210221 in words is "twenty-one billion, three hundred eleven million, two hundred ten thousand, two hundred twenty-one".