21113523 has 12 divisors (see below), whose sum is σ = 30539080. Its totient is φ = 14056416.

The previous prime is 21113467. The next prime is 21113527. The reversal of 21113523 is 32531112.

It is not a de Polignac number, because 21113523 - 2⁶ = 21113459 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21113496 and 21113505.

It is not an unprimeable number, because it can be changed into a prime (21113527) 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 11 ways as a sum of consecutive naturals, for example, 9063 + ... + 11151.

Almost surely, 2^21113523 is an apocalyptic number.

21113523 is a deficient number, since it is larger than the sum of its proper divisors (9425557).

21113523 is a wasteful number, since it uses less digits than its factorization.

21113523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3218 (or 3215 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21113523 is about 4594.9453750834. The cubic root of 21113523 is about 276.3886694861.

Adding to 21113523 its reverse (32531112), we get a palindrome (53644635).

The spelling of 21113523 in words is "twenty-one million, one hundred thirteen thousand, five hundred twenty-three".