21044805 has 16 divisors (see below), whose sum is σ = 34134720. Its totient is φ = 11069568.

The previous prime is 21044797. The next prime is 21044813. The reversal of 21044805 is 50844012.

It is an interprime number because it is at equal distance from previous prime (21044797) and next prime (21044813).

It is not a de Polignac number, because 21044805 - 2³ = 21044797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8515 + ... + 10704.

It is an arithmetic number, because the mean of its divisors is an integer number (2133420).

Almost surely, 2^21044805 is an apocalyptic number.

It is an amenable number.

21044805 is a deficient number, since it is larger than the sum of its proper divisors (13089915).

21044805 is a wasteful number, since it uses less digits than its factorization.

21044805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19300.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21044805 is about 4587.4617164615. The cubic root of 21044805 is about 276.0884903190.

Adding to 21044805 its reverse (50844012), we get a palindrome (71888817).

The spelling of 21044805 in words is "twenty-one million, forty-four thousand, eight hundred five".