21044536 has 16 divisors (see below), whose sum is σ = 40731840. Its totient is φ = 10182720.

The previous prime is 21044531. The next prime is 21044557. The reversal of 21044536 is 63544012.

It is a self number, because there is not a number n which added to its sum of digits gives 21044536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42181 + ... + 42676.

It is an arithmetic number, because the mean of its divisors is an integer number (2545740).

Almost surely, 2^21044536 is an apocalyptic number.

It is an amenable number.

21044536 is a deficient number, since it is larger than the sum of its proper divisors (19687304).

21044536 is a wasteful number, since it uses less digits than its factorization.

21044536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84894 (or 84890 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 21044536 is about 4587.4323973221. The cubic root of 21044536 is about 276.0873139698.

Adding to 21044536 its reverse (63544012), we get a palindrome (84588548).

The spelling of 21044536 in words is "twenty-one million, forty-four thousand, five hundred thirty-six".