21336565 has 8 divisors (see below), whose sum is σ = 25964928. Its totient is φ = 16828560.

The previous prime is 21336559. The next prime is 21336569. The reversal of 21336565 is 56563312.

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

It is not a de Polignac number, because 21336565 - 2¹⁵ = 21303797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21336569) 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, 29697 + ... + 30406.

It is an arithmetic number, because the mean of its divisors is an integer number (3245616).

Almost surely, 2^21336565 is an apocalyptic number.

It is an amenable number.

21336565 is a deficient number, since it is larger than the sum of its proper divisors (4628363).

21336565 is an equidigital number, since it uses as much as digits as its factorization.

21336565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60179.

The product of its digits is 16200, while the sum is 31.

The square root of 21336565 is about 4619.1519784480. The cubic root of 21336565 is about 277.3585134864.

Adding to 21336565 its reverse (56563312), we get a palindrome (77899877).

The spelling of 21336565 in words is "twenty-one million, three hundred thirty-six thousand, five hundred sixty-five".