21456089 has 2 divisors, whose sum is σ = 21456090. Its totient is φ = 21456088.

The previous prime is 21456077. The next prime is 21456103. The reversal of 21456089 is 98065412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16974400 + 4481689 = 4120^2 + 2117^2 .

It is a cyclic number.

It is not a de Polignac number, because 21456089 - 2¹⁶ = 21390553 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21456049) 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, 10728044 + 10728045.

It is an arithmetic number, because the mean of its divisors is an integer number (10728045).

Almost surely, 2^21456089 is an apocalyptic number.

It is an amenable number.

21456089 is a deficient number, since it is larger than the sum of its proper divisors (1).

21456089 is an equidigital number, since it uses as much as digits as its factorization.

21456089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 21456089 is about 4632.0717826908. The cubic root of 21456089 is about 277.8754553139.

The spelling of 21456089 in words is "twenty-one million, four hundred fifty-six thousand, eighty-nine".