21044385 has 24 divisors (see below), whose sum is σ = 38624040. Its totient is φ = 10563072.

The previous prime is 21044383. The next prime is 21044389. The reversal of 21044385 is 58344012.

21044385 is a `hidden beast` number, since 210 + 443 + 8 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 767376 + 20277009 = 876^2 + 4503^2 .

It is not a de Polignac number, because 21044385 - 2¹ = 21044383 is a prime.

It is a super-2 number, since 2×21044385² = 885732280056450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21044383) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12990 + ... + 14519.

It is an arithmetic number, because the mean of its divisors is an integer number (1609335).

Almost surely, 2^21044385 is an apocalyptic number.

It is an amenable number.

21044385 is a deficient number, since it is larger than the sum of its proper divisors (17579655).

21044385 is a wasteful number, since it uses less digits than its factorization.

21044385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27537 (or 27534 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 21044385 is about 4587.4159392843. The cubic root of 21044385 is about 276.0866536355.

Adding to 21044385 its reverse (58344012), we get a palindrome (79388397).

The spelling of 21044385 in words is "twenty-one million, forty-four thousand, three hundred eighty-five".