21529968 has 40 divisors (see below), whose sum is σ = 56182416. Its totient is φ = 7104000.

The previous prime is 21529957. The next prime is 21529979. The reversal of 21529968 is 86992512.

It is an interprime number because it is at equal distance from previous prime (21529957) and next prime (21529979).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2628 + ... + 7068.

Almost surely, 2^21529968 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 21529968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28091208).

21529968 is an abundant number, since it is smaller than the sum of its proper divisors (34652448).

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

21529968 is a wasteful number, since it uses less digits than its factorization.

21529968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4553 (or 4547 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The square root of 21529968 is about 4640.0396550030. The cubic root of 21529968 is about 278.1940228976.

The spelling of 21529968 in words is "twenty-one million, five hundred twenty-nine thousand, nine hundred sixty-eight".