21983968 has 36 divisors (see below), whose sum is σ = 44363592. Its totient is φ = 10723520.

The previous prime is 21983959. The next prime is 21983971. The reversal of 21983968 is 86938912.

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 5 ways as a sum of consecutive naturals, for example, 70533 + ... + 70843.

It is an arithmetic number, because the mean of its divisors is an integer number (1232322).

Almost surely, 2^21983968 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 21983968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22181796).

21983968 is an abundant number, since it is smaller than the sum of its proper divisors (22379624).

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

21983968 is an equidigital number, since it uses as much as digits as its factorization.

21983968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415 (or 360 counting only the distinct ones).

The product of its digits is 186624, while the sum is 46.

The square root of 21983968 is about 4688.7064314158. The cubic root of 21983968 is about 280.1358524428.

The spelling of 21983968 in words is "twenty-one million, nine hundred eighty-three thousand, nine hundred sixty-eight".