21023321321 has 2 divisors, whose sum is σ = 21023321322. Its totient is φ = 21023321320.

The previous prime is 21023321317. The next prime is 21023321401. The reversal of 21023321321 is 12312332012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20610622096 + 412699225 = 143564^2 + 20315^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023321321 - 2² = 21023321317 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21023321293 and 21023321302.

It is not a weakly prime, because it can be changed into another prime (21023321021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511660660 + 10511660661.

It is an arithmetic number, because the mean of its divisors is an integer number (10511660661).

Almost surely, 2^21023321321 is an apocalyptic number.

It is an amenable number.

21023321321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023321321 is an equidigital number, since it uses as much as digits as its factorization.

21023321321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21023321321 its reverse (12312332012), we get a palindrome (33335653333).

The spelling of 21023321321 in words is "twenty-one billion, twenty-three million, three hundred twenty-one thousand, three hundred twenty-one".