21285859 has 8 divisors (see below), whose sum is σ = 24399200. Its totient is φ = 18190656.

The previous prime is 21285857. The next prime is 21285893. The reversal of 21285859 is 95858212.

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

It is a cyclic number.

It is not a de Polignac number, because 21285859 - 2¹ = 21285857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21285857) 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, 1914 + ... + 6799.

It is an arithmetic number, because the mean of its divisors is an integer number (3049900).

Almost surely, 2^21285859 is an apocalyptic number.

21285859 is a deficient number, since it is larger than the sum of its proper divisors (3113341).

21285859 is an equidigital number, since it uses as much as digits as its factorization.

21285859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9069.

The product of its digits is 57600, while the sum is 40.

The square root of 21285859 is about 4613.6600438264. The cubic root of 21285859 is about 277.1386265417.

The spelling of 21285859 in words is "twenty-one million, two hundred eighty-five thousand, eight hundred fifty-nine".