21802424 has 64 divisors (see below), whose sum is σ = 50841600. Its totient is φ = 8553600.

The previous prime is 21802411. The next prime is 21802439. The reversal of 21802424 is 42420812.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21802424.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32654 + ... + 33314.

It is an arithmetic number, because the mean of its divisors is an integer number (794400).

Almost surely, 2^21802424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21802424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25420800).

21802424 is an abundant number, since it is smaller than the sum of its proper divisors (29039176).

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

21802424 is a wasteful number, since it uses less digits than its factorization.

21802424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724 (or 720 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 21802424 is about 4669.3065866358. The cubic root of 21802424 is about 279.3625977141.

The spelling of 21802424 in words is "twenty-one million, eight hundred two thousand, four hundred twenty-four".