21133824 has 40 divisors (see below), whose sum is σ = 56305920. Its totient is φ = 7044096.

The previous prime is 21133823. The next prime is 21133829. The reversal of 21133824 is 42833112.

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

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

It is a junction number, because it is equal to n+sod(n) for n = 21133794 and 21133803.

It is not an unprimeable number, because it can be changed into a prime (21133823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5344 + ... + 8415.

It is an arithmetic number, because the mean of its divisors is an integer number (1407648).

Almost surely, 2^21133824 is an apocalyptic number.

21133824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21133824 is an abundant number, since it is smaller than the sum of its proper divisors (35172096).

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

21133824 is an equidigital number, since it uses as much as digits as its factorization.

21133824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13780 (or 13764 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

The square root of 21133824 is about 4597.1539021442. The cubic root of 21133824 is about 276.4772251951.

Adding to 21133824 its reverse (42833112), we get a palindrome (63966936).

The spelling of 21133824 in words is "twenty-one million, one hundred thirty-three thousand, eight hundred twenty-four".