21231201317 has 2 divisors, whose sum is σ = 21231201318. Its totient is φ = 21231201316.

The previous prime is 21231201301. The next prime is 21231201319. The reversal of 21231201317 is 71310213212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19741936036 + 1489265281 = 140506^2 + 38591^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231201317 - 2⁴ = 21231201301 is a prime.

Together with 21231201319, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21231201292 and 21231201301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231201319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615600658 + 10615600659.

It is an arithmetic number, because the mean of its divisors is an integer number (10615600659).

Almost surely, 2^21231201317 is an apocalyptic number.

It is an amenable number.

21231201317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231201317 is an equidigital number, since it uses as much as digits as its factorization.

21231201317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 23.

Adding to 21231201317 its reverse (71310213212), we get a palindrome (92541414529).

The spelling of 21231201317 in words is "twenty-one billion, two hundred thirty-one million, two hundred one thousand, three hundred seventeen".