20658608685 has 128 divisors (see below), whose sum is σ = 43344806400. Its totient is φ = 9203466240.

The previous prime is 20658608653. The next prime is 20658608699. The reversal of 20658608685 is 58680685602.

20658608685 is a `hidden beast` number, since 20 + 6 + 5 + 8 + 608 + 6 + 8 + 5 = 666.

It is not a de Polignac number, because 20658608685 - 2⁵ = 20658608653 is a prime.

It is a super-2 number, since 2×20658608685² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4418509 + ... + 4423181.

It is an arithmetic number, because the mean of its divisors is an integer number (338631300).

Almost surely, 2^20658608685 is an apocalyptic number.

It is an amenable number.

20658608685 is an abundant number, since it is smaller than the sum of its proper divisors (22686197715).

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

20658608685 is a wasteful number, since it uses less digits than its factorization.

20658608685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4940 (or 4934 counting only the distinct ones).

The product of its (nonzero) digits is 5529600, while the sum is 54.

The spelling of 20658608685 in words is "twenty billion, six hundred fifty-eight million, six hundred eight thousand, six hundred eighty-five".