21113744 has 10 divisors (see below), whose sum is σ = 40907910. Its totient is φ = 10556864.

The previous prime is 21113723. The next prime is 21113773. The reversal of 21113744 is 44731112.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16096144 + 5017600 = 4012^2 + 2240^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659789 + ... + 659820.

It is an arithmetic number, because the mean of its divisors is an integer number (4090791).

Almost surely, 2^21113744 is an apocalyptic number.

It is an amenable number.

21113744 is a deficient number, since it is larger than the sum of its proper divisors (19794166).

21113744 is a wasteful number, since it uses less digits than its factorization.

21113744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1319617 (or 1319611 counting only the distinct ones).

The product of its digits is 672, while the sum is 23.

The square root of 21113744 is about 4594.9694231844. The cubic root of 21113744 is about 276.3896338236.

Adding to 21113744 its reverse (44731112), we get a palindrome (65844856).

The spelling of 21113744 in words is "twenty-one million, one hundred thirteen thousand, seven hundred forty-four".