21010444 has 48 divisors (see below), whose sum is σ = 45638208. Its totient is φ = 8241408.

The previous prime is 21010441. The next prime is 21010469. The reversal of 21010444 is 44401012.

It is not an unprimeable number, because it can be changed into a prime (21010441) 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 15 ways as a sum of consecutive naturals, for example, 71562 + ... + 71854.

It is an arithmetic number, because the mean of its divisors is an integer number (950796).

Almost surely, 2^21010444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21010444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22819104).

21010444 is an abundant number, since it is smaller than the sum of its proper divisors (24627764).

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

21010444 is a wasteful number, since it uses less digits than its factorization.

21010444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514 (or 512 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21010444 is about 4583.7150871318. The cubic root of 21010444 is about 275.9381468900.

Adding to 21010444 its reverse (44401012), we get a palindrome (65411456).

The spelling of 21010444 in words is "twenty-one million, ten thousand, four hundred forty-four".