21606113 has 8 divisors (see below), whose sum is σ = 22276968. Its totient is φ = 20939904.

The previous prime is 21606083. The next prime is 21606119. The reversal of 21606113 is 31160612.

It can be written as a sum of positive squares in 4 ways, for example, as 15618304 + 5987809 = 3952^2 + 2447^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21606113 - 2⁶ = 21606049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21606119) 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, 9845 + ... + 11837.

It is an arithmetic number, because the mean of its divisors is an integer number (2784621).

Almost surely, 2^21606113 is an apocalyptic number.

It is an amenable number.

21606113 is a deficient number, since it is larger than the sum of its proper divisors (670855).

21606113 is a wasteful number, since it uses less digits than its factorization.

21606113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2323.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21606113 is about 4648.2376230137. The cubic root of 21606113 is about 278.5215997911.

Adding to 21606113 its reverse (31160612), we get a palindrome (52766725).

The spelling of 21606113 in words is "twenty-one million, six hundred six thousand, one hundred thirteen".