21943589 has 2 divisors, whose sum is σ = 21943590. Its totient is φ = 21943588.

The previous prime is 21943543. The next prime is 21943609. The reversal of 21943589 is 98534912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21808900 + 134689 = 4670^2 + 367^2 .

It is a cyclic number.

It is not a de Polignac number, because 21943589 - 2⁸ = 21943333 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243589) 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, 10971794 + 10971795.

It is an arithmetic number, because the mean of its divisors is an integer number (10971795).

Almost surely, 2^21943589 is an apocalyptic number.

It is an amenable number.

21943589 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943589 is an equidigital number, since it uses as much as digits as its factorization.

21943589 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 41.

The square root of 21943589 is about 4684.3984672528. The cubic root of 21943589 is about 279.9642343773.

The spelling of 21943589 in words is "twenty-one million, nine hundred forty-three thousand, five hundred eighty-nine".