21064288 has 48 divisors (see below), whose sum is σ = 47706624. Its totient is φ = 8968320.

The previous prime is 21064273. The next prime is 21064291. The reversal of 21064288 is 88246012.

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, 60531 + ... + 60877.

It is an arithmetic number, because the mean of its divisors is an integer number (993888).

Almost surely, 2^21064288 is an apocalyptic number.

21064288 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21064288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23853312).

21064288 is an abundant number, since it is smaller than the sum of its proper divisors (26642336).

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

21064288 is a wasteful number, since it uses less digits than its factorization.

21064288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 21064288 is about 4589.5847306701. The cubic root of 21064288 is about 276.1736637219.

The spelling of 21064288 in words is "twenty-one million, sixty-four thousand, two hundred eighty-eight".