21113689 has 2 divisors, whose sum is σ = 21113690. Its totient is φ = 21113688.

The previous prime is 21113671. The next prime is 21113707. The reversal of 21113689 is 98631112.

It is a balanced prime because it is at equal distance from previous prime (21113671) and next prime (21113707).

It can be written as a sum of positive squares in only one way, i.e., 21086464 + 27225 = 4592^2 + 165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21113689 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21113689.

It is not a weakly prime, because it can be changed into another prime (21113629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556844 + 10556845.

It is an arithmetic number, because the mean of its divisors is an integer number (10556845).

Almost surely, 2^21113689 is an apocalyptic number.

It is an amenable number.

21113689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113689 is an equidigital number, since it uses as much as digits as its factorization.

21113689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 21113689 is about 4594.9634383747. The cubic root of 21113689 is about 276.3893938307.

The spelling of 21113689 in words is "twenty-one million, one hundred thirteen thousand, six hundred eighty-nine".