21004444 has 12 divisors (see below), whose sum is σ = 36855000. Its totient is φ = 10474448.

The previous prime is 21004387. The next prime is 21004447. The reversal of 21004444 is 44440012.

21004444 is a modest number, since divided by 4444 gives 2100 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5194 + ... + 8305.

It is an arithmetic number, because the mean of its divisors is an integer number (3071250).

Almost surely, 2^21004444 is an apocalyptic number.

It is an amenable number.

21004444 is a deficient number, since it is larger than the sum of its proper divisors (15850556).

21004444 is a wasteful number, since it uses less digits than its factorization.

21004444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13892 (or 13890 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 21004444 is about 4583.0605494582. The cubic root of 21004444 is about 275.9118776290.

Adding to 21004444 its reverse (44440012), we get a palindrome (65444456).

The spelling of 21004444 in words is "twenty-one million, four thousand, four hundred forty-four".