21089668 has 12 divisors (see below), whose sum is σ = 37532880. Its totient is φ = 10365992.

The previous prime is 21089659. The next prime is 21089671. The reversal of 21089668 is 86698012.

It is a self number, because there is not a number n which added to its sum of digits gives 21089668.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44446 + ... + 44917.

It is an arithmetic number, because the mean of its divisors is an integer number (3127740).

Almost surely, 2^21089668 is an apocalyptic number.

It is an amenable number.

21089668 is a deficient number, since it is larger than the sum of its proper divisors (16443212).

21089668 is a wasteful number, since it uses less digits than its factorization.

21089668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89426 (or 89424 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 21089668 is about 4592.3488543446. The cubic root of 21089668 is about 276.2845381767.

The spelling of 21089668 in words is "twenty-one million, eighty-nine thousand, six hundred sixty-eight".