21689344 has 44 divisors (see below), whose sum is σ = 44215200. Its totient is φ = 10631168.

The previous prime is 21689341. The next prime is 21689351. The reversal of 21689344 is 44398612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21689341) 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, 60237 + ... + 60595.

Almost surely, 2^21689344 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 21689344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22107600).

21689344 is an abundant number, since it is smaller than the sum of its proper divisors (22525856).

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

21689344 is an equidigital number, since it uses as much as digits as its factorization.

21689344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438 (or 420 counting only the distinct ones).

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

The square root of 21689344 is about 4657.1819805543. The cubic root of 21689344 is about 278.8787815460.

The spelling of 21689344 in words is "twenty-one million, six hundred eighty-nine thousand, three hundred forty-four".