21888256 has 36 divisors (see below), whose sum is σ = 47059012. Its totient is φ = 10100736.

The previous prime is 21888199. The next prime is 21888259. The reversal of 21888256 is 65288812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14137600 + 7750656 = 3760^2 + 2784^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21888259) 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, 40 + ... + 6616.

Almost surely, 2^21888256 is an apocalyptic number.

21888256 is a gapful number since it is divisible by the number (26) 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 21888256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23529506).

21888256 is an abundant number, since it is smaller than the sum of its proper divisors (25170756).

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

21888256 is an equidigital number, since it uses as much as digits as its factorization.

21888256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6606 (or 6592 counting only the distinct ones).

The product of its digits is 61440, while the sum is 40.

The square root of 21888256 is about 4678.4886448510. The cubic root of 21888256 is about 279.7287168390.

The spelling of 21888256 in words is "twenty-one million, eight hundred eighty-eight thousand, two hundred fifty-six".