21047444 has 12 divisors (see below), whose sum is σ = 40181568. Its totient is φ = 9567000.

The previous prime is 21047443. The next prime is 21047449. The reversal of 21047444 is 44474012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047441) 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, 239132 + ... + 239219.

It is an arithmetic number, because the mean of its divisors is an integer number (3348464).

Almost surely, 2^21047444 is an apocalyptic number.

It is an amenable number.

21047444 is a deficient number, since it is larger than the sum of its proper divisors (19134124).

21047444 is a wasteful number, since it uses less digits than its factorization.

21047444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478366 (or 478364 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 26.

The square root of 21047444 is about 4587.7493392730. The cubic root of 21047444 is about 276.1000302544.

The spelling of 21047444 in words is "twenty-one million, forty-seven thousand, four hundred forty-four".