20684513805 has 8 divisors (see below), whose sum is σ = 33095222112. Its totient is φ = 11031740688.

The previous prime is 20684513789. The next prime is 20684513809. The reversal of 20684513805 is 50831548602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20684513805 - 2⁴ = 20684513789 is a prime.

It is a super-2 number, since 2×20684513805² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20684513809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 689483779 + ... + 689483808.

It is an arithmetic number, because the mean of its divisors is an integer number (4136902764).

Almost surely, 2^20684513805 is an apocalyptic number.

It is an amenable number.

20684513805 is a deficient number, since it is larger than the sum of its proper divisors (12410708307).

20684513805 is a wasteful number, since it uses less digits than its factorization.

20684513805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1378967595.

The product of its (nonzero) digits is 230400, while the sum is 42.

The spelling of 20684513805 in words is "twenty billion, six hundred eighty-four million, five hundred thirteen thousand, eight hundred five".