21316317 has 16 divisors (see below), whose sum is σ = 32830272. Its totient is φ = 12158720.

The previous prime is 21316307. The next prime is 21316319. The reversal of 21316317 is 71361312.

It is a cyclic number.

It is not a de Polignac number, because 21316317 - 2¹¹ = 21314269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18438 + ... + 19559.

It is an arithmetic number, because the mean of its divisors is an integer number (2051892).

Almost surely, 2^21316317 is an apocalyptic number.

It is an amenable number.

21316317 is a deficient number, since it is larger than the sum of its proper divisors (11513955).

21316317 is a wasteful number, since it uses less digits than its factorization.

21316317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38028.

The product of its digits is 756, while the sum is 24.

The square root of 21316317 is about 4616.9597139243. The cubic root of 21316317 is about 277.2707497094.

Adding to 21316317 its reverse (71361312), we get a palindrome (92677629).

It can be divided in two parts, 2131 and 6317, that added together give a palindrome (8448).

The spelling of 21316317 in words is "twenty-one million, three hundred sixteen thousand, three hundred seventeen".