20689684 has 24 divisors (see below), whose sum is σ = 36989568. Its totient is φ = 10123680.

The previous prime is 20689661. The next prime is 20689699. The reversal of 20689684 is 48698602.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20689684.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 74554 + ... + 74830.

It is an arithmetic number, because the mean of its divisors is an integer number (1541232).

Almost surely, 2^20689684 is an apocalyptic number.

It is an amenable number.

20689684 is a deficient number, since it is larger than the sum of its proper divisors (16299884).

20689684 is a wasteful number, since it uses less digits than its factorization.

20689684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 615 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 20689684 is about 4548.5914303221. The cubic root of 20689684 is about 274.5267187218.

The spelling of 20689684 in words is "twenty million, six hundred eighty-nine thousand, six hundred eighty-four".