21406317 has 8 divisors (see below), whose sum is σ = 28760160. Its totient is φ = 14161680.

The previous prime is 21406279. The next prime is 21406339. The reversal of 21406317 is 71360412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21406317 - 2¹¹ = 21404269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406367) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26842 + ... + 27627.

It is an arithmetic number, because the mean of its divisors is an integer number (3595020).

Almost surely, 2^21406317 is an apocalyptic number.

It is an amenable number.

21406317 is a deficient number, since it is larger than the sum of its proper divisors (7353843).

21406317 is a wasteful number, since it uses less digits than its factorization.

21406317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54603.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 21406317 is about 4626.6961214240. The cubic root of 21406317 is about 277.6604250542.

Adding to 21406317 its reverse (71360412), we get a palindrome (92766729).

The spelling of 21406317 in words is "twenty-one million, four hundred six thousand, three hundred seventeen".