21226824 has 48 divisors (see below), whose sum is σ = 58020300. Its totient is φ = 7010304.

The previous prime is 21226823. The next prime is 21226831. The reversal of 21226824 is 42862212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18922500 + 2304324 = 4350^2 + 1518^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (21226823) 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 11 ways as a sum of consecutive naturals, for example, 6832 + ... + 9440.

Almost surely, 2^21226824 is an apocalyptic number.

21226824 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 21226824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29010150).

21226824 is an abundant number, since it is smaller than the sum of its proper divisors (36793476).

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

21226824 is a wasteful number, since it uses less digits than its factorization.

21226824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2734 (or 2727 counting only the distinct ones).

The product of its digits is 3072, while the sum is 27.

The square root of 21226824 is about 4607.2577527202. The cubic root of 21226824 is about 276.8821804279.

The spelling of 21226824 in words is "twenty-one million, two hundred twenty-six thousand, eight hundred twenty-four".