21031444 has 12 divisors (see below), whose sum is σ = 42062944. Its totient is φ = 9013464.

The previous prime is 21031433. The next prime is 21031457. The reversal of 21031444 is 44413012.

21031444 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 375534 + ... + 375589.

Almost surely, 2^21031444 is an apocalyptic number.

It is an amenable number.

21031444 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21031444 is a wasteful number, since it uses less digits than its factorization.

21031444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751134 (or 751132 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21031444 is about 4586.0052333158. The cubic root of 21031444 is about 276.0300499383.

Adding to 21031444 its reverse (44413012), we get a palindrome (65444456).

The spelling of 21031444 in words is "twenty-one million, thirty-one thousand, four hundred forty-four".