21616517 has 8 divisors (see below), whose sum is σ = 24030720. Its totient is φ = 19309680.

The previous prime is 21616501. The next prime is 21616549. The reversal of 21616517 is 71561612.

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

It is not a de Polignac number, because 21616517 - 2⁴ = 21616501 is a prime.

It is a super-2 number, since 2×21616517² = 934547614422578, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 21616517.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26417 + ... + 27222.

It is an arithmetic number, because the mean of its divisors is an integer number (3003840).

Almost surely, 2^21616517 is an apocalyptic number.

It is an amenable number.

21616517 is a deficient number, since it is larger than the sum of its proper divisors (2414203).

21616517 is a wasteful number, since it uses less digits than its factorization.

21616517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53683.

The product of its digits is 2520, while the sum is 29.

The square root of 21616517 is about 4649.3566221575. The cubic root of 21616517 is about 278.5662981554.

The spelling of 21616517 in words is "twenty-one million, six hundred sixteen thousand, five hundred seventeen".