21589605 has 48 divisors (see below), whose sum is σ = 40599360. Its totient is φ = 10883808.

The previous prime is 21589597. The next prime is 21589627. The reversal of 21589605 is 50698512.

It is a happy number.

It is not a de Polignac number, because 21589605 - 2³ = 21589597 is a prime.

It is a super-2 number, since 2×21589605² = 932222088112050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21589605.

It is a congruent number.

It is an unprimeable number.

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 in 47 ways as a sum of consecutive naturals, for example, 48514 + ... + 48956.

It is an arithmetic number, because the mean of its divisors is an integer number (845820).

Almost surely, 2^21589605 is an apocalyptic number.

It is an amenable number.

21589605 is a deficient number, since it is larger than the sum of its proper divisors (19009755).

21589605 is a wasteful number, since it uses less digits than its factorization.

21589605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495 (or 470 counting only the distinct ones).

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

The square root of 21589605 is about 4646.4615569269. The cubic root of 21589605 is about 278.4506475557.

The spelling of 21589605 in words is "twenty-one million, five hundred eighty-nine thousand, six hundred five".