21233404321 has 2 divisors, whose sum is σ = 21233404322. Its totient is φ = 21233404320.

The previous prime is 21233404319. The next prime is 21233404391. The reversal of 21233404321 is 12340433212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11875550625 + 9357853696 = 108975^2 + 96736^2 .

It is a cyclic number.

It is not a de Polignac number, because 21233404321 - 2¹ = 21233404319 is a prime.

It is a super-2 number, since 2×21233404321² (a number of 21 digits) contains 22 as substring.

Together with 21233404319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21233404391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616702160 + 10616702161.

It is an arithmetic number, because the mean of its divisors is an integer number (10616702161).

Almost surely, 2^21233404321 is an apocalyptic number.

It is an amenable number.

21233404321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233404321 is an equidigital number, since it uses as much as digits as its factorization.

21233404321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21233404321 its reverse (12340433212), we get a palindrome (33573837533).

The spelling of 21233404321 in words is "twenty-one billion, two hundred thirty-three million, four hundred four thousand, three hundred twenty-one".