21843968 has 26 divisors (see below), whose sum is σ = 43690794. Its totient is φ = 10919936.

The previous prime is 21843953. The next prime is 21843979. The reversal of 21843968 is 86934812.

It can be written as a sum of positive squares in only one way, i.e., 21827584 + 16384 = 4672^2 + 128^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1430 + ... + 6762.

Almost surely, 2^21843968 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 21843968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21845397).

21843968 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21843968 is an frugal number, since it uses more digits than its factorization.

21843968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5357 (or 5335 counting only the distinct ones).

The product of its digits is 82944, while the sum is 41.

The square root of 21843968 is about 4673.7530957465. The cubic root of 21843968 is about 279.5399247245.

The spelling of 21843968 in words is "twenty-one million, eight hundred forty-three thousand, nine hundred sixty-eight".