21075768 has 128 divisors (see below), whose sum is σ = 68428800. Its totient is φ = 5885568.

The previous prime is 21075749. The next prime is 21075773. The reversal of 21075768 is 86757012.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80005 + ... + 80267.

It is an arithmetic number, because the mean of its divisors is an integer number (534600).

Almost surely, 2^21075768 is an apocalyptic number.

21075768 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 21075768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34214400).

21075768 is an abundant number, since it is smaller than the sum of its proper divisors (47353032).

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

21075768 is a wasteful number, since it uses less digits than its factorization.

21075768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 21075768 is about 4590.8352181275. The cubic root of 21075768 is about 276.2238259976.

It can be divided in two parts, 2107 and 5768, that added together give a triangular number (7875 = T₁₂₅).

The spelling of 21075768 in words is "twenty-one million, seventy-five thousand, seven hundred sixty-eight".