21089684 has 24 divisors (see below), whose sum is σ = 46014528. Its totient is φ = 8216640.

The previous prime is 21089683. The next prime is 21089711. The reversal of 21089684 is 48698012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21089681) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 33929 + ... + 34544.

It is an arithmetic number, because the mean of its divisors is an integer number (1917272).

Almost surely, 2^21089684 is an apocalyptic number.

It is an amenable number.

21089684 is an abundant number, since it is smaller than the sum of its proper divisors (24924844).

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

21089684 is a wasteful number, since it uses less digits than its factorization.

21089684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68495 (or 68493 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 21089684 is about 4592.3505963722. The cubic root of 21089684 is about 276.2846080459.

The spelling of 21089684 in words is "twenty-one million, eighty-nine thousand, six hundred eighty-four".