21285393 has 8 divisors (see below), whose sum is σ = 28443168. Its totient is φ = 14158944.

The previous prime is 21285367. The next prime is 21285409. The reversal of 21285393 is 39358212.

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

It is not a de Polignac number, because 21285393 - 2⁸ = 21285137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21285293) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6196 + ... + 8997.

It is an arithmetic number, because the mean of its divisors is an integer number (3555396).

Almost surely, 2^21285393 is an apocalyptic number.

It is an amenable number.

21285393 is a deficient number, since it is larger than the sum of its proper divisors (7157775).

21285393 is a wasteful number, since it uses less digits than its factorization.

21285393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15663.

The product of its digits is 12960, while the sum is 33.

The square root of 21285393 is about 4613.6095413461. The cubic root of 21285393 is about 277.1366041107.

The spelling of 21285393 in words is "twenty-one million, two hundred eighty-five thousand, three hundred ninety-three".