21124536 has 32 divisors (see below), whose sum is σ = 53222400. Its totient is φ = 6986720.

The previous prime is 21124529. The next prime is 21124541. The reversal of 21124536 is 63542112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 216 + ... + 6503.

It is an arithmetic number, because the mean of its divisors is an integer number (1663200).

Almost surely, 2^21124536 is an apocalyptic number.

It is an amenable number.

21124536 is an abundant number, since it is smaller than the sum of its proper divisors (32097864).

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

21124536 is a wasteful number, since it uses less digits than its factorization.

21124536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6859 (or 6855 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 21124536 is about 4596.1436008898. The cubic root of 21124536 is about 276.4367167232.

Adding to 21124536 its reverse (63542112), we get a palindrome (84666648).

The spelling of 21124536 in words is "twenty-one million, one hundred twenty-four thousand, five hundred thirty-six".