21330684 has 36 divisors (see below), whose sum is σ = 54171936. Its totient is φ = 7076928.

The previous prime is 21330679. The next prime is 21330737. The reversal of 21330684 is 48603312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7117 + ... + 9659.

It is an arithmetic number, because the mean of its divisors is an integer number (1504776).

Almost surely, 2^21330684 is an apocalyptic number.

It is an amenable number.

21330684 is an abundant number, since it is smaller than the sum of its proper divisors (32841252).

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

21330684 is a wasteful number, since it uses less digits than its factorization.

21330684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2786 (or 2781 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21330684 is about 4618.5153458660. The cubic root of 21330684 is about 277.3330283579. Note that the first 3 decimals are identical.

Adding to 21330684 its reverse (48603312), we get a palindrome (69933996).

The spelling of 21330684 in words is "twenty-one million, three hundred thirty thousand, six hundred eighty-four".