21285849 has 8 divisors (see below), whose sum is σ = 30564352. Its totient is φ = 13098960.

The previous prime is 21285821. The next prime is 21285857. The reversal of 21285849 is 94858212.

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

It is not a de Polignac number, because 21285849 - 2⁹ = 21285337 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 545791 = 21285849 / (2 + 1 + 2 + 8 + 5 + 8 + 4 + 9).

It is not an unprimeable number, because it can be changed into a prime (21285749) 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, 272857 + ... + 272934.

It is an arithmetic number, because the mean of its divisors is an integer number (3820544).

Almost surely, 2^21285849 is an apocalyptic number.

It is an amenable number.

21285849 is a deficient number, since it is larger than the sum of its proper divisors (9278503).

21285849 is a wasteful number, since it uses less digits than its factorization.

21285849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545807.

The product of its digits is 46080, while the sum is 39.

The square root of 21285849 is about 4613.6589600880. The cubic root of 21285849 is about 277.1385831422.

The spelling of 21285849 in words is "twenty-one million, two hundred eighty-five thousand, eight hundred forty-nine".