21089768 has 16 divisors (see below), whose sum is σ = 45192480. Its totient is φ = 9038448.

The previous prime is 21089767. The next prime is 21089771. The reversal of 21089768 is 86798012.

It is not an unprimeable number, because it can be changed into a prime (21089767) 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, 188246 + ... + 188357.

It is an arithmetic number, because the mean of its divisors is an integer number (2824530).

Almost surely, 2^21089768 is an apocalyptic number.

21089768 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21089768 is an abundant number, since it is smaller than the sum of its proper divisors (24102712).

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

21089768 is a wasteful number, since it uses less digits than its factorization.

21089768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376616 (or 376612 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 21089768 is about 4592.3597420063. The cubic root of 21089768 is about 276.2849748583.

The spelling of 21089768 in words is "twenty-one million, eighty-nine thousand, seven hundred sixty-eight".