21113747 has 16 divisors (see below), whose sum is σ = 22766400. Its totient is φ = 19536000.

The previous prime is 21113723. The next prime is 21113773. The reversal of 21113747 is 74731112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21113747 - 2¹⁰ = 21112723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21113707) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 141629 + ... + 141777.

It is an arithmetic number, because the mean of its divisors is an integer number (1422900).

Almost surely, 2^21113747 is an apocalyptic number.

21113747 is a deficient number, since it is larger than the sum of its proper divisors (1652653).

21113747 is a wasteful number, since it uses less digits than its factorization.

21113747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334.

The product of its digits is 1176, while the sum is 26.

The square root of 21113747 is about 4594.9697496284. The cubic root of 21113747 is about 276.3896469141.

Adding to 21113747 its reverse (74731112), we get a palindrome (95844859).

The spelling of 21113747 in words is "twenty-one million, one hundred thirteen thousand, seven hundred forty-seven".