21065589 has 20 divisors (see below), whose sum is σ = 31711680. Its totient is φ = 13935240.

The previous prime is 21065563. The next prime is 21065599. The reversal of 21065589 is 98556012.

It is a happy number.

21065589 is a `hidden beast` number, since 2 + 10 + 65 + 589 = 666.

It is not a de Polignac number, because 21065589 - 2⁸ = 21065333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065549) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10324 + ... + 12194.

It is an arithmetic number, because the mean of its divisors is an integer number (1585584).

Almost surely, 2^21065589 is an apocalyptic number.

It is an amenable number.

21065589 is a deficient number, since it is larger than the sum of its proper divisors (10646091).

21065589 is a wasteful number, since it uses less digits than its factorization.

21065589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2022 (or 2013 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 21065589 is about 4589.7264624376. The cubic root of 21065589 is about 276.1793494041.

The spelling of 21065589 in words is "twenty-one million, sixty-five thousand, five hundred eighty-nine".