21124524 has 24 divisors (see below), whose sum is σ = 50438080. Its totient is φ = 6877584.

The previous prime is 21124501. The next prime is 21124529. The reversal of 21124524 is 42542112.

It is a self number, because there is not a number n which added to its sum of digits gives 21124524.

It is not an unprimeable number, because it can be changed into a prime (21124529) 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 7 ways as a sum of consecutive naturals, for example, 19954 + ... + 20985.

Almost surely, 2^21124524 is an apocalyptic number.

It is an amenable number.

21124524 is an abundant number, since it is smaller than the sum of its proper divisors (29313556).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21124524 is a wasteful number, since it uses less digits than its factorization.

21124524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40989 (or 40987 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 21124524 is about 4596.1422954473. The cubic root of 21124524 is about 276.4366643790.

Adding to 21124524 its reverse (42542112), we get a palindrome (63666636).

The spelling of 21124524 in words is "twenty-one million, one hundred twenty-four thousand, five hundred twenty-four".