21121311321 has 12 divisors (see below), whose sum is σ = 33282066480. Its totient is φ = 12800794680.

The previous prime is 21121311307. The next prime is 21121311359. The reversal of 21121311321 is 12311312112.

21121311321 is a `hidden beast` number, since 2 + 11 + 21 + 311 + 321 = 666.

It is not a de Polignac number, because 21121311321 - 2⁹ = 21121310809 is a prime.

It is a super-2 number, since 2×21121311321² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121311294 and 21121311303.

It is not an unprimeable number, because it can be changed into a prime (21121311371) 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 11 ways as a sum of consecutive naturals, for example, 106673191 + ... + 106673388.

It is an arithmetic number, because the mean of its divisors is an integer number (2773505540).

Almost surely, 2^21121311321 is an apocalyptic number.

It is an amenable number.

21121311321 is a deficient number, since it is larger than the sum of its proper divisors (12160755159).

21121311321 is a wasteful number, since it uses less digits than its factorization.

21121311321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213346596 (or 213346593 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 21121311321 its reverse (12311312112), we get a palindrome (33432623433).

The spelling of 21121311321 in words is "twenty-one billion, one hundred twenty-one million, three hundred eleven thousand, three hundred twenty-one".