21288944 has 10 divisors (see below), whose sum is σ = 41247360. Its totient is φ = 10644464.

The previous prime is 21288937. The next prime is 21288959. The reversal of 21288944 is 44988212.

It is a junction number, because it is equal to n+sod(n) for n = 21288898 and 21288907.

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 as a sum of consecutive naturals, namely, 665264 + ... + 665295.

It is an arithmetic number, because the mean of its divisors is an integer number (4124736).

Almost surely, 2^21288944 is an apocalyptic number.

It is an amenable number.

21288944 is a deficient number, since it is larger than the sum of its proper divisors (19958416).

21288944 is a wasteful number, since it uses less digits than its factorization.

21288944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1330567 (or 1330561 counting only the distinct ones).

The product of its digits is 36864, while the sum is 38.

The square root of 21288944 is about 4613.9943649727. The cubic root of 21288944 is about 277.1520146375.

The spelling of 21288944 in words is "twenty-one million, two hundred eighty-eight thousand, nine hundred forty-four".