21285359 has 4 divisors (see below), whose sum is σ = 21296016. Its totient is φ = 21274704.

The previous prime is 21285347. The next prime is 21285367. The reversal of 21285359 is 95358212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21285359 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 (21288359) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1334 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (5324004).

Almost surely, 2^21285359 is an apocalyptic number.

21285359 is a deficient number, since it is larger than the sum of its proper divisors (10657).

21285359 is an equidigital number, since it uses as much as digits as its factorization.

21285359 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10656.

The product of its digits is 21600, while the sum is 35.

The square root of 21285359 is about 4613.6058565942. The cubic root of 21285359 is about 277.1364565502.

The spelling of 21285359 in words is "twenty-one million, two hundred eighty-five thousand, three hundred fifty-nine".