21846816 has 72 divisors (see below), whose sum is σ = 64157184. Its totient is φ = 7044480.

The previous prime is 21846793. The next prime is 21846821. The reversal of 21846816 is 61864812.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is an unprimeable number.

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, 7705 + ... + 10151.

It is an arithmetic number, because the mean of its divisors is an integer number (891072).

Almost surely, 2^21846816 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 21846816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32078592).

21846816 is an abundant number, since it is smaller than the sum of its proper divisors (42310368).

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

21846816 is a wasteful number, since it uses less digits than its factorization.

21846816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2494 (or 2483 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 21846816 is about 4674.0577660102. The cubic root of 21846816 is about 279.5520729311.

The spelling of 21846816 in words is "twenty-one million, eight hundred forty-six thousand, eight hundred sixteen".