20516888687 has 4 divisors (see below), whose sum is σ = 20559721920. Its totient is φ = 20474055456.

The previous prime is 20516888681. The next prime is 20516888713. The reversal of 20516888687 is 78688861502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20516888687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20516888681) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 21415898 + ... + 21416855.

It is an arithmetic number, because the mean of its divisors is an integer number (5139930480).

Almost surely, 2^20516888687 is an apocalyptic number.

20516888687 is a deficient number, since it is larger than the sum of its proper divisors (42833233).

20516888687 is an equidigital number, since it uses as much as digits as its factorization.

20516888687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42833232.

The product of its (nonzero) digits is 10321920, while the sum is 59.

The spelling of 20516888687 in words is "twenty billion, five hundred sixteen million, eight hundred eighty-eight thousand, six hundred eighty-seven".