21330320321 has 2 divisors, whose sum is σ = 21330320322. Its totient is φ = 21330320320.

The previous prime is 21330320309. The next prime is 21330320357. The reversal of 21330320321 is 12302303312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11437233025 + 9893087296 = 106945^2 + 99464^2 .

It is a cyclic number.

It is not a de Polignac number, because 21330320321 - 2¹⁸ = 21330058177 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21330320293 and 21330320302.

It is not a weakly prime, because it can be changed into another prime (21330320521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665160160 + 10665160161.

It is an arithmetic number, because the mean of its divisors is an integer number (10665160161).

Almost surely, 2^21330320321 is an apocalyptic number.

It is an amenable number.

21330320321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21330320321 is an equidigital number, since it uses as much as digits as its factorization.

21330320321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 20.

Adding to 21330320321 its reverse (12302303312), we get a palindrome (33632623633).

The spelling of 21330320321 in words is "twenty-one billion, three hundred thirty million, three hundred twenty thousand, three hundred twenty-one".