21330312317 has 2 divisors, whose sum is σ = 21330312318. Its totient is φ = 21330312316.

The previous prime is 21330312281. The next prime is 21330312347. The reversal of 21330312317 is 71321303312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20576754916 + 753557401 = 143446^2 + 27451^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21330312317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21330312347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665156158 + 10665156159.

It is an arithmetic number, because the mean of its divisors is an integer number (10665156159).

Almost surely, 2^21330312317 is an apocalyptic number.

It is an amenable number.

21330312317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21330312317 is an equidigital number, since it uses as much as digits as its factorization.

21330312317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 26.

Adding to 21330312317 its reverse (71321303312), we get a palindrome (92651615629).

The spelling of 21330312317 in words is "twenty-one billion, three hundred thirty million, three hundred twelve thousand, three hundred seventeen".