20538718866 has 12 divisors (see below), whose sum is σ = 44500557582. Its totient is φ = 6846239616.

The previous prime is 20538718859. The next prime is 20538718867. The reversal of 20538718866 is 66881783502.

20538718866 is a `hidden beast` number, since 20 + 5 + 387 + 188 + 66 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18914225841 + 1624493025 = 137529^2 + 40305^2 .

It is not an unprimeable number, because it can be changed into a prime (20538718867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 570519951 + ... + 570519986.

Almost surely, 2^20538718866 is an apocalyptic number.

20538718866 is an abundant number, since it is smaller than the sum of its proper divisors (23961838716).

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

20538718866 is a wasteful number, since it uses less digits than its factorization.

20538718866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141039945 (or 1141039942 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 20538718866 in words is "twenty billion, five hundred thirty-eight million, seven hundred eighteen thousand, eight hundred sixty-six".