20687788056 has 64 divisors (see below), whose sum is σ = 55819098720. Its totient is φ = 6351621120.

The previous prime is 20687788049. The next prime is 20687788057. The reversal of 20687788056 is 65088778602.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 20687787987 and 20687788005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687788057) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 71916 + ... + 215748.

Almost surely, 2^20687788056 is an apocalyptic number.

20687788056 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a pronic number, being equal to 143832×143833.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20687788056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27909549360).

20687788056 is an abundant number, since it is smaller than the sum of its proper divisors (35131310664).

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

20687788056 is a wasteful number, since it uses less digits than its factorization.

20687788056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144316 (or 144312 counting only the distinct ones).

The product of its (nonzero) digits is 9031680, while the sum is 57.

The spelling of 20687788056 in words is "twenty billion, six hundred eighty-seven million, seven hundred eighty-eight thousand, fifty-six".