21329688 has 16 divisors (see below), whose sum is σ = 53324280. Its totient is φ = 7109888.

The previous prime is 21329683. The next prime is 21329699. The reversal of 21329688 is 88692312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21329683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 444345 + ... + 444392.

Almost surely, 2^21329688 is an apocalyptic number.

It is an amenable number.

21329688 is an abundant number, since it is smaller than the sum of its proper divisors (31994592).

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

21329688 is a wasteful number, since it uses less digits than its factorization.

21329688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 888746 (or 888742 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 21329688 is about 4618.4075177489. The cubic root of 21329688 is about 277.3287117594.

The spelling of 21329688 in words is "twenty-one million, three hundred twenty-nine thousand, six hundred eighty-eight".