21064128 has 56 divisors (see below), whose sum is σ = 57546240. Its totient is φ = 6792960.

The previous prime is 21064117. The next prime is 21064133. The reversal of 21064128 is 82146012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21064098 and 21064107.

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, 4183 + ... + 7721.

Almost surely, 2^21064128 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 21064128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28773120).

21064128 is an abundant number, since it is smaller than the sum of its proper divisors (36482112).

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

21064128 is a wasteful number, since it uses less digits than its factorization.

21064128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3585 (or 3575 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21064128 is about 4589.5672998661. The cubic root of 21064128 is about 276.1729644673.

The spelling of 21064128 in words is "twenty-one million, sixty-four thousand, one hundred twenty-eight".