21089966 has 8 divisors (see below), whose sum is σ = 31727160. Its totient is φ = 10514248.

The previous prime is 21089953. The next prime is 21089969. The reversal of 21089966 is 66998012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21089969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14501 + ... + 15888.

It is an arithmetic number, because the mean of its divisors is an integer number (3965895).

Almost surely, 2^21089966 is an apocalyptic number.

21089966 is a deficient number, since it is larger than the sum of its proper divisors (10637194).

21089966 is a wasteful number, since it uses less digits than its factorization.

21089966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30738.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 21089966 is about 4592.3812995003. The cubic root of 21089966 is about 276.2858394838.

The spelling of 21089966 in words is "twenty-one million, eighty-nine thousand, nine hundred sixty-six".