21863424 has 88 divisors (see below), whose sum is σ = 63669888. Its totient is φ = 6615040.

The previous prime is 21863423. The next prime is 21863483. The reversal of 21863424 is 42436812.

It is a tau number, because it is divible by the number of its divisors (88).

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 = 21863391 and 21863400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21863423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33469 + ... + 34115.

Almost surely, 2^21863424 is an apocalyptic number.

21863424 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 21863424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31834944).

21863424 is an abundant number, since it is smaller than the sum of its proper divisors (41806464).

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

21863424 is a wasteful number, since it uses less digits than its factorization.

21863424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681 (or 663 counting only the distinct ones).

The product of its digits is 9216, while the sum is 30.

The square root of 21863424 is about 4675.8340432483. The cubic root of 21863424 is about 279.6228936987.

The spelling of 21863424 in words is "twenty-one million, eight hundred sixty-three thousand, four hundred twenty-four".