21360806321 has 2 divisors, whose sum is σ = 21360806322. Its totient is φ = 21360806320.

The previous prime is 21360806309. The next prime is 21360806387. The reversal of 21360806321 is 12360806312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12728352400 + 8632453921 = 112820^2 + 92911^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21360806321 is a prime.

It is not a weakly prime, because it can be changed into another prime (21360808321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10680403160 + 10680403161.

It is an arithmetic number, because the mean of its divisors is an integer number (10680403161).

Almost surely, 2^21360806321 is an apocalyptic number.

It is an amenable number.

21360806321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21360806321 is an equidigital number, since it uses as much as digits as its factorization.

21360806321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 32.

Subtracting from 21360806321 its reverse (12360806312), we obtain a palindrome (9000000009).

The spelling of 21360806321 in words is "twenty-one billion, three hundred sixty million, eight hundred six thousand, three hundred twenty-one".