21124530 has 64 divisors (see below), whose sum is σ = 64385280. Its totient is φ = 4828032.

The previous prime is 21124529. The next prime is 21124541. The reversal of 21124530 is 3542112.

21124530 is a `hidden beast` number, since 211 + 2 + 453 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 31 ways as a sum of consecutive naturals, for example, 3699 + ... + 7478.

It is an arithmetic number, because the mean of its divisors is an integer number (1006020).

Almost surely, 2^21124530 is an apocalyptic number.

21124530 is an abundant number, since it is smaller than the sum of its proper divisors (43260750).

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

21124530 is a wasteful number, since it uses less digits than its factorization.

21124530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11200 (or 11194 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21124530 is about 4596.1429481686. The cubic root of 21124530 is about 276.4366905511.

Adding to 21124530 its reverse (3542112), we get a palindrome (24666642).

The spelling of 21124530 in words is "twenty-one million, one hundred twenty-four thousand, five hundred thirty".