21136824 has 96 divisors (see below), whose sum is σ = 60652800. Its totient is φ = 6639360.

The previous prime is 21136813. The next prime is 21136837. The reversal of 21136824 is 42863112.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 110569 + ... + 110759.

It is an arithmetic number, because the mean of its divisors is an integer number (631800).

Almost surely, 2^21136824 is an apocalyptic number.

21136824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21136824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30326400).

21136824 is an abundant number, since it is smaller than the sum of its proper divisors (39515976).

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

21136824 is a wasteful number, since it uses less digits than its factorization.

21136824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285 (or 278 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21136824 is about 4597.4801794026. The cubic root of 21136824 is about 276.4903067909.

Adding to 21136824 its reverse (42863112), we get a palindrome (63999936).

The spelling of 21136824 in words is "twenty-one million, one hundred thirty-six thousand, eight hundred twenty-four".