21010044 has 24 divisors (see below), whose sum is σ = 53480448. Its totient is φ = 6366640.

The previous prime is 21010037. The next prime is 21010049. The reversal of 21010044 is 44001012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79452 + ... + 79715.

It is an arithmetic number, because the mean of its divisors is an integer number (2228352).

Almost surely, 2^21010044 is an apocalyptic number.

It is an amenable number.

21010044 is an abundant number, since it is smaller than the sum of its proper divisors (32470404).

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

21010044 is a wasteful number, since it uses less digits than its factorization.

21010044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159185 (or 159183 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21010044 is about 4583.6714541948. The cubic root of 21010044 is about 275.9363957615.

Adding to 21010044 its reverse (44001012), we get a palindrome (65011056).

The spelling of 21010044 in words is "twenty-one million, ten thousand, forty-four".