21108768 has 96 divisors (see below), whose sum is σ = 58931712. Its totient is φ = 6604800.

The previous prime is 21108757. The next prime is 21108793. The reversal of 21108768 is 86780112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121930 + ... + 122102.

It is an arithmetic number, because the mean of its divisors is an integer number (613872).

Almost surely, 2^21108768 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 21108768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29465856).

21108768 is an abundant number, since it is smaller than the sum of its proper divisors (37822944).

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

21108768 is a wasteful number, since it uses less digits than its factorization.

21108768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 21108768 is about 4594.4279295686. The cubic root of 21108768 is about 276.3679193284.

It can be divided in two parts, 2110 and 8768, that added together give a triangular number (10878 = T₁₄₇).

The spelling of 21108768 in words is "twenty-one million, one hundred eight thousand, seven hundred sixty-eight".