20861885187 has 24 divisors (see below), whose sum is σ = 35401989168. Its totient is φ = 11670984000.

The previous prime is 20861885173. The next prime is 20861885243. The reversal of 20861885187 is 78158816802.

20861885187 is a `hidden beast` number, since 2 + 0 + 8 + 618 + 8 + 5 + 18 + 7 = 666.

It is not a de Polignac number, because 20861885187 - 2⁴ = 20861885171 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20861885687) 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 23 ways as a sum of consecutive naturals, for example, 8103564 + ... + 8106137.

It is an arithmetic number, because the mean of its divisors is an integer number (1475082882).

Almost surely, 2^20861885187 is an apocalyptic number.

20861885187 is a deficient number, since it is larger than the sum of its proper divisors (14540103981).

20861885187 is a wasteful number, since it uses less digits than its factorization.

20861885187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16209731 (or 16209728 counting only the distinct ones).

The product of its (nonzero) digits is 1720320, while the sum is 54.

The spelling of 20861885187 in words is "twenty billion, eight hundred sixty-one million, eight hundred eighty-five thousand, one hundred eighty-seven".