21608113 has 2 divisors, whose sum is σ = 21608114. Its totient is φ = 21608112.

The previous prime is 21608099. The next prime is 21608123. The reversal of 21608113 is 31180612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17164449 + 4443664 = 4143^2 + 2108^2 .

It is a cyclic number.

It is not a de Polignac number, because 21608113 - 2¹⁷ = 21477041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21608123) 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 as a sum of consecutive naturals, namely, 10804056 + 10804057.

It is an arithmetic number, because the mean of its divisors is an integer number (10804057).

Almost surely, 2^21608113 is an apocalyptic number.

It is an amenable number.

21608113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21608113 is an equidigital number, since it uses as much as digits as its factorization.

21608113 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 21608113 is about 4648.4527533363. The cubic root of 21608113 is about 278.5301934394.

Adding to 21608113 its reverse (31180612), we get a palindrome (52788725).

The spelling of 21608113 in words is "twenty-one million, six hundred eight thousand, one hundred thirteen".