21017317 has 2 divisors, whose sum is σ = 21017318. Its totient is φ = 21017316.

The previous prime is 21017303. The next prime is 21017327. The reversal of 21017317 is 71371012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13883076 + 7134241 = 3726^2 + 2671^2 .

It is a cyclic number.

It is not a de Polignac number, because 21017317 - 2⁷ = 21017189 is a prime.

It is a super-2 number, since 2×21017317² = 883455227756978, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21017327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508658 + 10508659.

It is an arithmetic number, because the mean of its divisors is an integer number (10508659).

Almost surely, 2^21017317 is an apocalyptic number.

It is an amenable number.

21017317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21017317 is an equidigital number, since it uses as much as digits as its factorization.

21017317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 21017317 is about 4584.4647452020. The cubic root of 21017317 is about 275.9682321834.

Adding to 21017317 its reverse (71371012), we get a palindrome (92388329).

The spelling of 21017317 in words is "twenty-one million, seventeen thousand, three hundred seventeen".