21012222321 has 24 divisors (see below), whose sum is σ = 30946115304. Its totient is φ = 13734927360.

The previous prime is 21012222317. The next prime is 21012222323. The reversal of 21012222321 is 12322221012.

21012222321 is a `hidden beast` number, since 210 + 1 + 222 + 232 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 98724096 + 20913498225 = 9936^2 + 144615^2 .

It is not a de Polignac number, because 21012222321 - 2² = 21012222317 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21012222294 and 21012222303.

It is not an unprimeable number, because it can be changed into a prime (21012222323) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 113665 + ... + 234401.

It is an arithmetic number, because the mean of its divisors is an integer number (1289421471).

Almost surely, 2^21012222321 is an apocalyptic number.

It is an amenable number.

21012222321 is a deficient number, since it is larger than the sum of its proper divisors (9933892983).

21012222321 is a wasteful number, since it uses less digits than its factorization.

21012222321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121121 (or 121118 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21012222321 its reverse (12322221012), we get a palindrome (33334443333).

The spelling of 21012222321 in words is "twenty-one billion, twelve million, two hundred twenty-two thousand, three hundred twenty-one".