21013122321 has 6 divisors (see below), whose sum is σ = 30352287810. Its totient is φ = 14008748208.

The previous prime is 21013122311. The next prime is 21013122329. The reversal of 21013122321 is 12322131012.

21013122321 is a `hidden beast` number, since 210 + 13 + 122 + 321 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11100729600 + 9912392721 = 105360^2 + 99561^2 .

It is not a de Polignac number, because 21013122321 - 2¹¹ = 21013120273 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21013122294 and 21013122303.

It is not an unprimeable number, because it can be changed into a prime (21013122329) 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 5 ways as a sum of consecutive naturals, for example, 1167395676 + ... + 1167395693.

It is an arithmetic number, because the mean of its divisors is an integer number (5058714635).

Almost surely, 2^21013122321 is an apocalyptic number.

It is an amenable number.

21013122321 is a deficient number, since it is larger than the sum of its proper divisors (9339165489).

21013122321 is a wasteful number, since it uses less digits than its factorization.

21013122321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2334791375 (or 2334791372 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21013122321 its reverse (12322131012), we get a palindrome (33335253333).

The spelling of 21013122321 in words is "twenty-one billion, thirteen million, one hundred twenty-two thousand, three hundred twenty-one".