21040444 has 12 divisors (see below), whose sum is σ = 38008768. Its totient is φ = 10180800.

The previous prime is 21040427. The next prime is 21040447. The reversal of 21040444 is 44404012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040447) 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, 84717 + ... + 84964.

Almost surely, 2^21040444 is an apocalyptic number.

It is an amenable number.

21040444 is a deficient number, since it is larger than the sum of its proper divisors (16968324).

21040444 is a wasteful number, since it uses less digits than its factorization.

21040444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169716 (or 169714 counting only the distinct ones).

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

The square root of 21040444 is about 4586.9863745165. The cubic root of 21040444 is about 276.0694182316.

Adding to 21040444 its reverse (44404012), we get a palindrome (65444456).

The spelling of 21040444 in words is "twenty-one million, forty thousand, four hundred forty-four".