21109744 has 20 divisors (see below), whose sum is σ = 41003824. Its totient is φ = 10528128.

The previous prime is 21109727. The next prime is 21109763. The reversal of 21109744 is 44790112.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 5869 + ... + 8755.

Almost surely, 2^21109744 is an apocalyptic number.

It is an amenable number.

21109744 is a deficient number, since it is larger than the sum of its proper divisors (19894080).

21109744 is a wasteful number, since it uses less digits than its factorization.

21109744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3352 (or 3346 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21109744 is about 4594.5341439584. The cubic root of 21109744 is about 276.3721787106.

Adding to 21109744 its reverse (44790112), we get a palindrome (65899856).

The spelling of 21109744 in words is "twenty-one million, one hundred nine thousand, seven hundred forty-four".