21646016 has 56 divisors (see below), whose sum is σ = 51694080. Its totient is φ = 8785152.

The previous prime is 21646003. The next prime is 21646021. The reversal of 21646016 is 61064612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (56).

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, 7241 + ... + 9783.

Almost surely, 2^21646016 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 21646016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25847040).

21646016 is an abundant number, since it is smaller than the sum of its proper divisors (30048064).

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

21646016 is a wasteful number, since it uses less digits than its factorization.

21646016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2581 (or 2571 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21646016 is about 4652.5279150157. The cubic root of 21646016 is about 278.6929558109.

The spelling of 21646016 in words is "twenty-one million, six hundred forty-six thousand, sixteen".