21143303317 has 2 divisors, whose sum is σ = 21143303318. Its totient is φ = 21143303316.

The previous prime is 21143303263. The next prime is 21143303351. The reversal of 21143303317 is 71330334112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20303115121 + 840188196 = 142489^2 + 28986^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21143303317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143303387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571651658 + 10571651659.

It is an arithmetic number, because the mean of its divisors is an integer number (10571651659).

Almost surely, 2^21143303317 is an apocalyptic number.

It is an amenable number.

21143303317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143303317 is an equidigital number, since it uses as much as digits as its factorization.

21143303317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 28.

Adding to 21143303317 its reverse (71330334112), we get a palindrome (92473637429).

The spelling of 21143303317 in words is "twenty-one billion, one hundred forty-three million, three hundred three thousand, three hundred seventeen".