21111321321 has 12 divisors (see below), whose sum is σ = 30509010948. Its totient is φ = 14067346464.

The previous prime is 21111321299. The next prime is 21111321347. The reversal of 21111321321 is 12312311112.

21111321321 is a `hidden beast` number, since 2 + 11 + 11 + 321 + 321 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3677816025 + 17433505296 = 60645^2 + 132036^2 .

It is not a de Polignac number, because 21111321321 - 2⁵ = 21111321289 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21111321294 and 21111321303.

It is not an unprimeable number, because it can be changed into a prime (21111325321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 552810 + ... + 589763.

It is an arithmetic number, because the mean of its divisors is an integer number (2542417579).

Almost surely, 2^21111321321 is an apocalyptic number.

It is an amenable number.

21111321321 is a deficient number, since it is larger than the sum of its proper divisors (9397689627).

21111321321 is a wasteful number, since it uses less digits than its factorization.

21111321321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144632 (or 1144629 counting only the distinct ones).

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

Adding to 21111321321 its reverse (12312311112), we get a palindrome (33423632433).

The spelling of 21111321321 in words is "twenty-one billion, one hundred eleven million, three hundred twenty-one thousand, three hundred twenty-one".