21302431321 has 2 divisors, whose sum is σ = 21302431322. Its totient is φ = 21302431320.

The previous prime is 21302431303. The next prime is 21302431331. The reversal of 21302431321 is 12313420312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12873171600 + 8429259721 = 113460^2 + 91811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21302431321 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21302431292 and 21302431301.

It is not a weakly prime, because it can be changed into another prime (21302431331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651215660 + 10651215661.

It is an arithmetic number, because the mean of its divisors is an integer number (10651215661).

Almost surely, 2^21302431321 is an apocalyptic number.

It is an amenable number.

21302431321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21302431321 is an equidigital number, since it uses as much as digits as its factorization.

21302431321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 21302431321 its reverse (12313420312), we get a palindrome (33615851633).

The spelling of 21302431321 in words is "twenty-one billion, three hundred two million, four hundred thirty-one thousand, three hundred twenty-one".