21589205 has 8 divisors (see below), whose sum is σ = 28262304. Its totient is φ = 15701200.

The previous prime is 21589171. The next prime is 21589207. The reversal of 21589205 is 50298512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21589205 - 2¹⁶ = 21523669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21589207) 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 in 7 ways as a sum of consecutive naturals, for example, 196211 + ... + 196320.

It is an arithmetic number, because the mean of its divisors is an integer number (3532788).

Almost surely, 2^21589205 is an apocalyptic number.

It is an amenable number.

21589205 is a deficient number, since it is larger than the sum of its proper divisors (6673099).

21589205 is a wasteful number, since it uses less digits than its factorization.

21589205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392547.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 21589205 is about 4646.4185132207. The cubic root of 21589205 is about 278.4489278863.

The spelling of 21589205 in words is "twenty-one million, five hundred eighty-nine thousand, two hundred five".