21489844 has 12 divisors (see below), whose sum is σ = 37723168. Its totient is φ = 10711800.

The previous prime is 21489833. The next prime is 21489877. The reversal of 21489844 is 44898412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21489797 and 21489806.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 6792 + ... + 9439.

Almost surely, 2^21489844 is an apocalyptic number.

It is an amenable number.

21489844 is a deficient number, since it is larger than the sum of its proper divisors (16233324).

21489844 is a wasteful number, since it uses less digits than its factorization.

21489844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16566 (or 16564 counting only the distinct ones).

The product of its digits is 73728, while the sum is 40.

The square root of 21489844 is about 4635.7139687431. The cubic root of 21489844 is about 278.0210980658.

The spelling of 21489844 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred forty-four".