21608075 has 6 divisors (see below), whose sum is σ = 26794044. Its totient is φ = 17286440.

The previous prime is 21608039. The next prime is 21608077. The reversal of 21608075 is 57080612.

It is not a de Polignac number, because 21608075 - 2²² = 17413771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21608077) 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 5 ways as a sum of consecutive naturals, for example, 432137 + ... + 432186.

It is an arithmetic number, because the mean of its divisors is an integer number (4465674).

Almost surely, 2^21608075 is an apocalyptic number.

21608075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21608075 is a deficient number, since it is larger than the sum of its proper divisors (5185969).

21608075 is an equidigital number, since it uses as much as digits as its factorization.

21608075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864333 (or 864328 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 21608075 is about 4648.4486659530. The cubic root of 21608075 is about 278.5300301651.

Adding to 21608075 its reverse (57080612), we get a palindrome (78688687).

The spelling of 21608075 in words is "twenty-one million, six hundred eight thousand, seventy-five".