21002031317 has 2 divisors, whose sum is σ = 21002031318. Its totient is φ = 21002031316.

The previous prime is 21002031313. The next prime is 21002031359. The reversal of 21002031317 is 71313020012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20894991601 + 107039716 = 144551^2 + 10346^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002031317 - 2² = 21002031313 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002031313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501015658 + 10501015659.

It is an arithmetic number, because the mean of its divisors is an integer number (10501015659).

Almost surely, 2^21002031317 is an apocalyptic number.

It is an amenable number.

21002031317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002031317 is an equidigital number, since it uses as much as digits as its factorization.

21002031317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 252, while the sum is 20.

Adding to 21002031317 its reverse (71313020012), we get a palindrome (92315051329).

The spelling of 21002031317 in words is "twenty-one billion, two million, thirty-one thousand, three hundred seventeen".