21859446 has 64 divisors (see below), whose sum is σ = 52462080. Its totient is φ = 5940480.

The previous prime is 21859429. The next prime is 21859447. The reversal of 21859446 is 64495812.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859447) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 159490 + ... + 159626.

It is an arithmetic number, because the mean of its divisors is an integer number (819720).

Almost surely, 2^21859446 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21859446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26231040).

21859446 is an abundant number, since it is smaller than the sum of its proper divisors (30602634).

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

21859446 is a wasteful number, since it uses less digits than its factorization.

21859446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309.

The product of its digits is 69120, while the sum is 39.

The square root of 21859446 is about 4675.4086452416. The cubic root of 21859446 is about 279.6059337547.

The spelling of 21859446 in words is "twenty-one million, eight hundred fifty-nine thousand, four hundred forty-six".