21317417 has 12 divisors (see below), whose sum is σ = 24008628. Its totient is φ = 18902400.

The previous prime is 21317377. The next prime is 21317419. The reversal of 21317417 is 71471312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5285401 + 16032016 = 2299^2 + 4004^2 .

It is not a de Polignac number, because 21317417 - 2²⁴ = 4540201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21317419) 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 in 11 ways as a sum of consecutive naturals, for example, 2813 + ... + 7109.

It is an arithmetic number, because the mean of its divisors is an integer number (2000719).

Almost surely, 2^21317417 is an apocalyptic number.

It is an amenable number.

21317417 is a deficient number, since it is larger than the sum of its proper divisors (2691211).

21317417 is a wasteful number, since it uses less digits than its factorization.

21317417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4360 (or 4349 counting only the distinct ones).

The product of its digits is 1176, while the sum is 26.

The square root of 21317417 is about 4617.0788383999. The cubic root of 21317417 is about 277.2755190227.

Adding to 21317417 its reverse (71471312), we get a palindrome (92788729).

The spelling of 21317417 in words is "twenty-one million, three hundred seventeen thousand, four hundred seventeen".