20505684 has 12 divisors (see below), whose sum is σ = 47846624. Its totient is φ = 6835224.

The previous prime is 20505679. The next prime is 20505691. The reversal of 20505684 is 48650502.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 854392 + ... + 854415.

Almost surely, 2^20505684 is an apocalyptic number.

It is an amenable number.

20505684 is an abundant number, since it is smaller than the sum of its proper divisors (27340940).

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

20505684 is a wasteful number, since it uses less digits than its factorization.

20505684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1708814 (or 1708812 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 20505684 is about 4528.3202183591. The cubic root of 20505684 is about 273.7104761437.

The spelling of 20505684 in words is "twenty million, five hundred five thousand, six hundred eighty-four".