21443968 has 96 divisors (see below), whose sum is σ = 53721360. Its totient is φ = 8451072.

The previous prime is 21443941. The next prime is 21443999. The reversal of 21443968 is 86934412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81405 + ... + 81667.

Almost surely, 2^21443968 is an apocalyptic number.

21443968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21443968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26860680).

21443968 is an abundant number, since it is smaller than the sum of its proper divisors (32277392).

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

21443968 is a wasteful number, since it uses less digits than its factorization.

21443968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 285 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 21443968 is about 4630.7632200319. The cubic root of 21443968 is about 277.8231195436.

The spelling of 21443968 in words is "twenty-one million, four hundred forty-three thousand, nine hundred sixty-eight".