20987188887 has 16 divisors (see below), whose sum is σ = 31983904512. Its totient is φ = 11991394560.

The previous prime is 20987188847. The next prime is 20987188889. The reversal of 20987188887 is 78888178902.

It is not a de Polignac number, because 20987188887 - 2⁸ = 20987188631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20987188889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 168583 + ... + 265319.

It is an arithmetic number, because the mean of its divisors is an integer number (1998994032).

Almost surely, 2^20987188887 is an apocalyptic number.

20987188887 is a deficient number, since it is larger than the sum of its proper divisors (10996715625).

20987188887 is a wasteful number, since it uses less digits than its factorization.

20987188887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107078.

The product of its (nonzero) digits is 28901376, while the sum is 66.

The spelling of 20987188887 in words is "twenty billion, nine hundred eighty-seven million, one hundred eighty-eight thousand, eight hundred eighty-seven".