21456064 has 56 divisors (see below), whose sum is σ = 49743360. Its totient is φ = 8990976.

The previous prime is 21456059. The next prime is 21456067. The reversal of 21456064 is 46065412.

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

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21456067) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20547 + ... + 21565.

Almost surely, 2^21456064 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 21456064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24871680).

21456064 is an abundant number, since it is smaller than the sum of its proper divisors (28287296).

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

21456064 is a wasteful number, since it uses less digits than its factorization.

21456064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1085 (or 1075 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 21456064 is about 4632.0690841135. The cubic root of 21456064 is about 277.8753473898.

The spelling of 21456064 in words is "twenty-one million, four hundred fifty-six thousand, sixty-four".